Managing Japanese knotweedon development sites
the knotweedcode of practice
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on
The Environment Agency wish tothank Defra and Network Rail for theircontribution towards the cost ofproduction of this code.
Managing Japanese knotweedon development sites
the knotweedcode of practice
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We are the Environment Agency. It’s our job to look after yourenvironment and make it a better place – for you, and forfuture generations.
Your environment is the air you breathe, the water you drinkand the ground you walk on. Working with business,Government and society as a whole, we are making yourenvironment cleaner and healthier.
The Environment Agency. Out there, making your environmenta better place.
Published by:
Environment Agency
Rio House
Waterside Drive, Aztec West
Almondsbury, Bristol BS32 4UD
Tel: 0870 8506506
Email: [email protected]
www.environment-agency.wales.gov.uk
© Environment Agency
All rights reserved. This document may be reproduced with
prior permission of the Environment Agency.
Published - September 2006.
EA Japanese Knotweed Cover SETUP 12/9/06 5:21 pm Page 2
Contents
Contents 02
Summary 04
Introduction 05
ManagingJapaneseknotweed–legislation 06
Thestatusofthiscode 08
Tipsfordevelopers 09
1 EcologicalinformationonJapaneseknotweed 10 1.1-WhatisJapaneseknotweed?
1.2-WhatdoesJapaneseknotweedlooklike?
1.3-Regeneration
1.4-Dispersal
1.5-WhydoIneedtomanageJapaneseknotweedonmydevelopmentsite?
FlowchartfortreatingJapaneseknotweed 12
2 HowdoIpreventJapaneseknotweedspreading? 13
2.1-Avoidingcontaminationaroundthesite
2.2-Goodsitehygiene
2.3-Avoidingnewcontaminationtothesite
2.4-Reusingtreatedsoilsonsite
3 HowdoImanagemyJapaneseknotweedproblem? 15
3.1- Japaneseknotweedmanagementplans
3.2-Herbicidetreatment
3.3-WhichherbicideshouldIuse?
3.4-Combinedtreatmentmethods
4 HowdoIuserootbarriermembranes? 20 4.1-Cellformation
4.2-Protectingstructuresandhardsurfaces
4.3-Preventinghorizontalspread
4.4-Protectingservices,etc
5 HowdoItreatordisposeofJapaneseknotweedonsite? 28 5.1-CuttingJapaneseknotweedcanes
5.2-Burning
5.3-Excavation
5.4-Theburialmethod
5.5-Thebundmethod
6 HowdoIdisposeofJapaneseknotweedoff-site? 32 6.1-Arrangementsforlandfill
6.2-Dutyofcareforhauliers
Contents
7 HowdoImovesoilcontainingJapaneseknotweed? 34
7.1- Movingsoilon-site
7.2- Movingsoiloff-site
7.3- Decontaminatingvehicles
8 HowwillJapaneseknotweedaffectusingthesiteinthe 35
longterm? 8.1-ManagingburiedJapaneseknotweedinthelongterm
8.2-Controllingpotentialregrowtharoundthesite
8.3-Advicetonewowners
8.4-WhatdoIdoifJapaneseknotweedstartstogrowthroughtarmac
andotherengineeredsurfacesandstructures?
8.5-HowdoIstopJapaneseknotweedfromneighbouringproperties
reinfestingthesite?
8.6-HowdoItreatJapaneseknotweedregrowthamongstvaluable
shrubsandplantingschemes?
9 Sourcesofadditionalinformation 38 9.1-Additionalinformation
9.2-Someusefulresources
Glossary 41
Appendix
I AguidetoidentifyingandexcavatingJapaneseknotweedrhizome i)WhatisJapaneseknotweed?
ii)WhatisJapaneseknotweedrhizome?
iii)WhyisitimportanttobeabletoidentifyJapaneseknotweedrhizome?
iv)HowdoIrecogniserhizome?
v)HowdoIremoverhizome?
II Root/rhizomeidentificationchart
III Root/rhizomeidentificationchart–othercommonplants
IV TableforidentifyingJapaneseknotweedrhizome
V TemplateJapaneseknotweedmanagementplan
VI AnexampleofaJapaneseknotweedmanagementplan.
VII Restrictedaccesssign
2 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites3
Summary
Thiscodereplaces“TheEnvironmentAgencycodeofpracticeforthemanagement,destructionanddisposalofJapaneseknotweed”May2001.
This code of practice will help developers manage Japanese knotweed legally. It also gives you options for cost effectively managing Japanese knotweed on site. Architects, planners, designers, contractors, consultants and landscape gardeners can also use this code.
JapaneseknotweedFallopia japonica var japonica isanon-nativeinvasivespeciesofplant.SinceitwasintroducedintotheUKasanornamentalgardenplantinthemid-nineteenthcenturyithasspreadacrosstheUK,particularlyalongwatercourses,transportroutesandinfestedwasteareas.
Plantswithintheirnativerangeareusuallycontrolledbyavarietyofnaturalpestsanddiseases.Whentheseplantsareintroducedintonewareasthatarefreefromthesepestsanddiseases,theycanbecomelargerandmorevigorous.Theyinvadenaturalhabitatsandout-competethenativeplantsandanimalsthatnormallylivethere.Rivers,hedges,roadsidesandrailwaysformimportantcorridorsfornativeplantsandanimalstomigrate,andlargeinfestationsofnon-nativeweedscanblocktheseroutesforwildlife.
Japaneseknotweedisn’tjustaproblemforournativewildlife.Thevigorousgrowthcandamagebuildingsandhardsurfaces.Onceestablishedunderneathoraroundthebuiltenvironment,itcanbeparticularlyhardtocontrol.RiversideJapaneseknotweeddamagesflooddefencestructuresandreducesthecapacityofchannelstocarryfloodwater.
Footpathsbecomecrowdedwithtallcanes,makingitdifficultforpedestrianstoseeandmakingthemfeellesssafe.Inwinter,thetalldeadcanesshow
wherelitterhasbecomecaughtupandratscanlivethere.Lawnsandgardensbecomeinfestedandthecostofmaintainingbuildingsincreases.
ThereareanumberofwaysinwhichwecanmanagetheimpactofJapaneseknotweed.ItisimportantthatwefindoutthewaysinwhichJapaneseknotweedhasbeenspreadandtrytotacklethese.DisposingofsoilfromdevelopmentsitesisonewayJapaneseknotweedhasspread.
Brownfielddevelopmentisanimportantaspectofurbanandruralregenerationandprotectinggreenbelt.ManyofthesesitessupportinfestationsofJapaneseknotweed,whichcanliveinpoorsoilqualityandcontaminationcommontotheseareas.Thesesiteshaveoftenbeenusedtoreceivewaste,oftenfly-tippedbygardeners.
IntroductionPurposeThiscodehasbeenwrittenforanyoneinvolvedinthedevelopmentandhaulageindustrywhomayencountersiteswithJapaneseknotweed,orsoilcontainingit.Itallowsourstafftoprovideconsistentadvice.
ManaginglandinfestedbyJapaneseknotweedinatimelyandappropriatewaycanavoid:
• excessivecost
• potentialprosecutionand/orcompensationclaims
• physicaldamagetobuildingsandhardsurfaces
• harmtotheenvironment.
IdentifyingJapaneseknotweedonasiteearlyletsdevelopersassessandcostoptionsfordestroying,disposingofandmanagingit,aswellasnegotiatinganappropriatechangeinthepurchasepriceoftheland.
YoushouldkeeptheamountofJapaneseknotweed-infestedsoilyouexcavatetoaminimum.
MakingsureyourstaffcanidentifyJapaneseknotweedrhizomecanreducewastecostsandimprovehowyoumanageJapaneseknotweedonsite.
DonotaccepttopsoiluntilyouhaveinspecteditforJapaneseknotweedrhizome.
Japaneseknotweed-infestedsoilthathasbeentreatedcanbereusedforlandscapingthesite,butshouldnotbetakenoffsite,unlesstolandfill.
DesignatingaclerkofworkstooverseetheJapaneseknotweedmanagementplanisagoodwayofensuringthatcontractorstreatJapaneseknotweedinanappropriatemanner.
YouhaveachoiceofherbicidesthatareeffectiveagainstJapaneseknotweed,dependingonyoursituation.
ItisanoffencetoplantorcauseJapaneseknotweedtospreadinthewildundertheWildlifeandCountrysideAct1981andallwastecontainingJapaneseknotweedcomesunderthecontrolofPartIIoftheEnvironmentalProtectionAct1990.
Youcangetadviceonmanagingwastefromusonourcustomerservicesline;08708506506
Ifyouseeanyoneillegallymovingordisposingofwaste,callourincidenthotlineon;0800807060.
4 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites5
ManagingJapaneseknotweed-legislationLegislationcoveringthehandling
anddisposalofknotweedincludes
thefollowing:
The Control of Pesticides Regulations 1986requireanypersonwhousesapesticidetotakeallreasonableprecautionstoprotectthehealthofhumanbeings,creaturesandplants,safeguardtheenvironmentandinparticularavoidthepollutionofwater.ForapplicationofpesticidesinornearwaterapprovalfromtheEnvironmentAgencyshouldbesoughtbeforeuse.
Section14(2)oftheWildlife and Countryside Act 1981 (WCA 1981)statesthat“ifanypersonplantsorotherwisecausestogrowinthewildanyplantwhichisincludedinPartIIofSchedule9,heshallbeguiltyofanoffence.”JapaneseknotweedisoneoftheplantslistedintheSchedule.AnyoneconvictedofanoffenceunderSection14oftheWCA1981mayfaceafineof£5,000and/or6monthsimprisonment,or2yearsand/oranunlimitedfineonindictment.
TheEnvironmental Protection Act 1990 (EPA 1990)containsanumberoflegalprovisionsconcerning“controlledwaste”,whicharesetoutinPartII.AnyJapaneseknotweedcontaminatedsoilorplantmaterialthatyoudiscard,intendtodiscardorarerequiredtodiscardislikelytobeclassifiedascontrolledwaste.Themostrelevantprovisionsarein:
section33(1a)and(1b)whichcreateoffencestodowiththedeposit,treating,keepingordisposingofcontrolledwastewithoutalicence.Exemptionsfromlicensingareavailableinsomecircumstances,andaresetoutinSchedule3totheWasteManagementLicensingRegulations1994asamended(theWMLR1994)s.33(1c)whichmakesitanoffencetokeep,treatordisposeofcontrolledwasteinamannerlikelytocasepollutionoftheenvironmentorharmtohumanhealth.
section34placesdutiesonanypersonwhoimports,produces,carries,keeps,treatsordisposesofcontrolledwaste.Wastemustbehandledresponsiblyandinaccordancewiththelawatallstagesbetweenitsproductionandfinalrecoveryordisposal.Wastemustbetransferredtoanauthorisedperson,inotherwordsapersonwhoiseitheraregisteredcarrierorexemptedfromregistrationbytheControlled Waste (Registration of Carriers and Seizure of Vehicles) Regulations 1991.Awastetransfernotemustbecompletedandsignedgivingawrittendescriptionofthewaste,whichissufficienttoenablethereceiverofthewastetohandleitinaccordancewiththeirowndutyofcare.TheprovisionsconcerningwastetransfernotesaresetoutintheEnvironmental Protection (Duty of Care) Regulations 1991(asamended).Failuretocomplywiththeseprovisionsisanoffence.
TheHazardous Waste Regulations 2005 (HWR 2005)containprovisionsaboutthehandlingandmovementofhazardouswaste.Consignmentnotesmustbecompletedwhenanyhazardouswasteistransferred,whichincludedetailsaboutthehazardouspropertiesandanyspecialhandlingrequirements.Ifaconsignmentnoteiscompleted,awastetransfernoteisnotnecessary.UntreatedJapaneseknotweedisnotclassedashazardouswaste,butmaterialcontainingknotweedwhichhasbeentreatedwithcertainherbicides,maybeclassifiedashazardouswaste.
TheWaste Management Licensing Regulations 1994describe‘wasterelevantobjectives’inParagraph4ofSchedule4.Theseobjectivesrequirethatwasteisrecoveredordisposedof“withoutendangeringhumanhealthandwithoutusingprocessesormethodswhichcouldharmtheenvironmentandinparticularwithout–risktowater,air,soil,plantsoranimals;orcausingnuisancethoughnoiseorodours;oradverselyaffectingthecountrysideorplacesofspecialinterest”
Theabovelegalprovisionshaveconsequencesforarangeofpeople,includinganybodyinvolvedinthemanagementordisposalofknotweed.Forexampleknotweedwhichiscutdownorexcavatedandremovedfromadevelopmentsitemustbetransferredtoanauthorisedperson,andcorrectlydescribed.Itmustbedisposedofappropriately,assetoutbelowinthisCode.Ifyouaregoingtoburyknotweedonthedevelopmentsiteyouwillneedtoconsultusfirsttomakesurethatthematerialdoesnotcontainanyothercontaminantthatmayaffectthequalityofgroundwater.Ifyoupollutetheenvironmentorcauseharmtohumanhealthyoumaybeprosecuted.Anyonewhousesaherbicidemustensurethattheydonotpollutethewaterenvironmentandtheuseofherbicidesinornearwaterrequiresapprovalfromus.
Ifanywastesoilorknotweedissentforlandfilleitherbeforeorafteranytreatment,itmustgotoalandfillthatisauthorisedtoreceiveit.
ItisnotanoffencetohaveJapaneseknotweedonyourlandanditisnotanotifiableweed.AllowingJapaneseknotweedtogrowontootherpeoplespropertymayberegardedasaprivatenuisanceundercommonlaw,butthiswouldbeacivilmatter.
OurroleTheEnvironmentAgencyisresponsibleforregulatingwaste.Wegrantwastemanagementlicences,registerexemptionsandcantakeenforcementactionincludingprosecutionifthelawisnotcompliedwith.WegiveapprovalsundertheControlofPesticidesRegulations1986foruseofpesticidesinornearwater.
WemaytakeenforcementactionunderWCA1981,buttherearealsoanumberofotherorganisationsthatcandoso.Wewouldnotnormallyusethislegislationunlessawasteoffencehadalsobeencommitted.
We are not responsible for controlling Japanese knotweed, other than that growing on our land. Managing knotweed is the responsibility of the owner/occupier of a site. We do not endorse Japanese knotweed management plans, or endorse companies that do this.
6 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites7
Whereyourelyonthemethodsofonsiteknotweedmanagementinparagraphs4.1,5.4and5.5thiswouldnormallyrequireyoutohaveawastemanagementlicenceorapollutionpreventionandcontrolpermit.
Howeverifyoucarryouttheseactivitiesinfullaccordancewiththiscodeofpractice,andtheworkmeetsthewasterelevantobjectivesdescribedabove,theninaccordancewithourEnforcementandProsecutionPolicywewouldnotnormallyprosecuteforfailuretohaveawastemanagementlicenceorpermit.
ThestatusanduseofthisCodeProvidedthereisasuitablelocation,thiscodedescribeswaysofmanagingJapaneseknotweedthatdevelopersmaywishtoconsider,whichwillavoidcreatingawastedisposalproblem.WearekeentoprovidealternativesthatallowdeveloperstotreatJapaneseknotweedonsite,soyoudon’thavetouselandfill.Landfillisveryexpensiveforthedevelopmentindustry,itreducesvaluablelandfillcapacityandneedshaulage,whichdamagestheenvironmentandincreasestheriskofJapaneseknotweedspreading.Sometimes,duetoshortageoftimeandlocation,landfillistheonlyreliableoption,butitshouldbetreatedasalastresort.
ThereareanumberofwaysofmanagingJapaneseknotweedwithinadevelopmentsite.SitemanagersneedtobecarefulofclaimsmadeaboutproductsandmethodsonofferforcontrollingJapaneseknotweed,particularlythosethatclaimitcanquicklydestroytheproblemcompletely.
Wecannotguaranteethatanyofthemethodswedescribeinthiscodewillbesuccessful.Webelievethemethodswithinthiscodeareamongthebestthatarecurrentlyavailable,butdonotreflectthecompletechoicethatisavailable.Thecontractorandclientneedtoagreeacontractforeffectivelytreatingtheproblem.RememberthatJapaneseknotweedcanstaydormantformanyyears.
Youmaywishtousethiscodeofpracticetoassistyouincarryingoutyourlegaldutiesconcerningknotweed.Howeverthiscodedoesnotconstitutelegaladviceanditdoesnotaimtogiveadetailedorcomprehensiveaccountofthelegislationthatcouldapplytoyou.Youshouldbeawarethatisyourresponsibilitytomakesurethatthelawiscompliedwith.Wastelegislationisespeciallycomplex.Youneedtodiscusstheseissueswithustomakesureyouactappropriately.
Ifyouneedadvice,callourcustomer
serviceslineon08708506506.Ifyou
seeanyoneillegallymovingordisposing
ofwaste,callourincidenthotlineon
0800807060.
Muchoftheinformationinthiscodeconcerningon-sitetreatmentoptionsisaimedatsuggestingbestpracticeratherthansettingoutlegalobligations.
ThiscodeshouldbeusedinconjunctionwithotherguidanceorregulationsconcerningJapaneseknotweedifrelevant,suchasthemodelspecificationandtenderdocumentsproducedbytheformerWelshDevelopmentAgency,nowpartoftheWelshAssemblyGovernment.
TipsfordevelopersWehopethat,bydevelopingthiscode,wewillhelpindustrytoavoidexcessivecosts,
protecttheenvironmentandusenaturalresourcesinasustainableway.Wewould
encouragedeveloperstoconsiderthefollowingparticularpoints:
Check for Japanese knotweed before buying a site.
a) Theinformationandinternetlinkswithinthis codeshouldbeenoughforyoutofindoutabout Japaneseknotweedinitsvariousforms.Ifthere isJapaneseknotweedonasite,thisshouldnot stopyoubuyingit,butyouwillneedtoconsider thiswhenworkingouthowprofitablea developmentislikelytobe.
b) Ifasitehasbeenskimmedortreated,lookfor evidenceofJapaneseknotweedmaterial. Considersomeformoflegalprotectionfromthe potentialsubsequentcostofmanagingJapanese knotweedwithinthepurchaseagreement.
c) IfthereisJapaneseknotweed,considerwhether youwillbeabletotreatthematerialonsite. Haveyouboughtenoughspacetoshiftsoiland createabund,forinstance?
d) IfyouthinkthereisnoJapaneseknotweedon thesite,considergettinglegalguaranteesthat saythisbeforeyoubuythesite.
Timetable for treatment and development.
a) PlantominimisetheamountofJapanese knotweedthatyouhavetoexcavate.
b) Makesureyouhaveallocatedenoughtime withintheprojecttimescaletodevelopandapply aJapaneseknotweedmanagementplan.
c) TreatingJapaneseknotweedearlyandeffectively cansignificantlyreducethechanceofitgrowing again.Youshouldagreeandimplementa treatmentplanassoonaspossible.
d) Considerphasingthedevelopment,toallow moretimetotreattheproblem.
e) Usethebestmethods,includingthemost effectiveherbicidesforthesiteinquestion. Thiswillbedeterminedbyfactorssuchashow closethesiteistocontrolledwatersand desirabletreesandothervegetation.
Managing treated material.Justbecausesoilhasbeentreated,thisdoesnotmeanJapaneseknotweedcannotgrowagain.However,ifsoilistreatedeffectively,itcanbecleanenoughtobeusedforlandscapingwithinthedevelopment.
Youshouldonlyusetreatedsoilinlocalisedareas,whereJapaneseknotweedcontrolmethodscouldeasilybeused,ifmaterialstartstogrowagain.Weadvisethatyoushouldnotusetreatedsoilwithin50mofawatercourse.
Long-term management.YouneedtoconsiderthechancethatJapaneseknotweedcouldgrowbackwhenyouaremanagingthesitelong-term.
Currentownersofthesiteneedtoaccuratelyrecordwithinthedeedsofthepropertywhereanymaterialisburiedandmakethisavailabletoallsubsequentownerssothematerialisnotdisturbed.
Asummaryofthetreatmentshouldbeincludedwithinthevendorstatementdeclaration.
8 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites9
Spring
Winter
Development site for sale. Would you have spotted the telltale dead winter canes that indicated this site was infested with knotweed?
1.1 What is Japanese knotweed?Japaneseknotweedisatall,vigorousornamentalplantthatescapedfromcultivationinthelatenineteenthcenturytobecomeanaggressiveinvaderintheurbanandruralenvironment.
1.2 What does Japanese knotweed look like?Japaneseknotweed,scientificnamesFallopia japonica(Houtt.RonseDecraene),Reynoutria japonica(Houtt.)orPolygonum cuspidatum(Siebold&Zuccarini)isamemberofthedockfamily(Polygonaceae).Itisarhizomatous(producesundergroundstems)perennialplantwithdistinctive,branching,hollow,bamboo-likestems,coveredinpurplespeckles,oftenreaching2-3mhigh.Theleavesofthematureplantareupto120mminlengthwithaflattenedbaseandpointedtipandarearrangedonarchingstemsinazig-zagpattern.Theplantflowerslateintheseason,AugusttoOctober,withsmallcreamy-whiteflowershanginginclustersfromtheleafaxils(pointatwhichtheleafjoinswiththestem).Theundergroundrhizomesarethickandwoodywithaknottyappearanceandwhenbrokenrevealabrightorange-colouredcentre.Therhizomesystemmayextendto,andbeyond,adepthofatleast2mandextend7mlaterallyfromaparentplant.
Duringwinter,theleavesdiebacktorevealorange/browncolouredwoodystemswhichmaystayerectforseveralyears.Stemandleafmaterialdecomposesslowly,leavingadeeplayerofplantlitter.DuringMarchtoApril,theplantsendsupnewshoots,red/purpleincolourwithrolledbackleaves.Theseshootsgrowrapidlyduetostorednutrientsintheextensiverhizomesystem.Growthratesofupto40mmadayhavebeenrecorded.
1.3 RegenerationOnlyfemaleJapaneseknotweed(F. japonica var japonica)plantshavebeenrecordedtodateintheUK.Althoughseedsareproduced,theyarenottrueJapaneseknotweedseedsbuthybrids,andrarelysurvive.
EcologicalinformationonJapaneseknotweed
Zig-zag pattern Purple speckles
Alternate leaves
August - October flowers
2-3 metre high canes
Spring Growth
TwospeciescloselyrelatedtoJapaneseknotweedarealsofoundintheUK.Theseare,giantknotweed(Fallopia sachalinensis),amuchtallerplantwhichreachesaheightof5m;andasmallercompactvariety(Fallopia japonica var. compacta),whichgrowstoaheightofonly1m.Thehybrid(Fallopia x bohemica)(acrossbetweenJapaneseknotweedandgiantknotweed)isalsofoundthroughouttheUKbutisnotascommonasJapaneseknotweed.BothgiantknotweedandthehybridshouldbemanagedinthesamewayasJapaneseknotweed.
Japaneseknotweedrarelyproducesviableseeds.IntheUKtheplantismainlyspreadthroughrhizomefragmentsorcutstems.Greenhousetrialshaveshownthataslittleas0.7gramofrhizomematerial(10mminlength)canproduceanewplantwithin10days.Cutfreshstemshavealsobeenshowntoproduceshootsandrootsfromnodeswhenburiedinsoilorimmersedinwater.Oncecutstemmaterialhasbeenallowedtodryoutthoroughlyandhasreachedtheorange/brown‘woody’stage,thereisnofurtherregeneration.Rhizomematerialmaytakemuchlongertodieandmayremaindormantforlongperiods,possiblyaslongas20years.
1.4 DispersalThespreadandhighregenerationratesoftheplanthaveseriousimplicationsfordispersalbybothnaturalandhumanmeans.Inrivercatchments,fragmentsofrhizomesorcutstemsthatarewashedintowatercoursesunderhighwaterflowscanformnewplantsdownstream.Fly-tippinggardenwastethatcontainsstemorrhizomefragments,usingcontaminatedtopsoilandtransportingsoilfrominfestedsitesduringconstructionworks
arethemainwaysthatpeoplespreadtheplant.Smallfragmentsofstemandrhizomemayalsobetransferredfromaninfestedsitetoothersitesonmachinery,forexampleforbuildingworksorformaintainingroadverges.
1.5 Why do I need to manage Japanese knotweed on my development site?HabitatsaffectedbyJapaneseknotweedincludethoseinbothurbanandruralareas.Inanurbanenvironment,sitessuchasroadverges,railwaylandandwatercoursecorridorsmaybeaffected.Wasteground,cemeteriesandheavilydisturbedgroundareparticularlyvulnerable.Inruralareas,theproblemsincludedisruptingsightlinesonroadsandrailwaysand,intheriversideenvironment,disruptingflooddefencestructures.Theplantdamagestheurbanenvironmentbypushingupthroughtarmacandpaving,out-competingotherspeciesinplantingprogrammesaspartoflandscapingschemesandcausingaestheticproblemsaslitteraccumulatesinthedensethicketsformedbytheplant.Thisalsoencouragesvermin.
JapaneseknotweedisalsoinvadingcontinentalEurope,particularlyintheeast.ItisalsocausingproblemsonthewesternseaboardoftheUnitedStates.Withinitsnativerange,Japaneseknotweedrarelycausesproblems.
JapaneseknotweedhasbeenremovedfromthenaturalenemiesthatcontrolitinitsnativerangeinJapan.Itout-competesournativeplantsandanimals.ThespreadofJapaneseknotweedisaseriousthreattoourcountryside,andthenativeplantsandanimalsthatrelyuponit.
Hybrid knotweed F.x bohemica
Giant knotweed F.sachalinensis
Dead winter canes
10 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites11
FlowchartfortreatingJapaneseknotweed
ItisimportanttomakesurethatthesiteisnotcontaminatedbyfreshJapanese
knotweed,orthatpartsofthesitepreviouslyunaffectedbyJapaneseknotweeddo
notbecomecontaminated.Werecommendthat:
YES
YES
YES
Is there Japanese knotweed on site? NO
NO
NO
Can the site be treated in the long term (> 3 years)?
Does the infested soil area need to be disturbed?
can the site be treated in the medium-term
(more than 18 months)?
Is there enough appropriate space for a bund (see Section
5.5) for 18 months?
Can a root barrier membrane cell be safely buried at least 2m deep within
the site?
Can the infested soil be buried up to5m deep within the site?
HerbicideRefer to Sections:
• 2 to avoid Japanese knotweed spreading further
• 3 to plan how you will treat it
• 8 for managing in the long term Soil only suitable for reusing on site.
Bund methodRefer to Sections:
• 5 (particularly 5.5) for treatment and Appendix I for guidance on removing rhizomes
• 7 for moving soil
• 2 to avoid Japanese knotweed spreading further
• 8 for managing it in the long term
Soil only suitable for reuse on site.
Burial methodRefer to Sections:
• 5 (particularly 5.4) for treatment and Appendix 1 for guidance on removing rhizomes
• 7 for moving soil
• 2 to avoid Japanese knotweed spreading further
• 8 for managing it in the long-term. Do not use a persistent herbicide.
Root barrier membraneRefer to Sections:
• 4 for guidance on using root barrier membrane and Appendix 1 for guidance on removing rhizomes
• 7 for moving soil
• 2 to avoid Japanese knotweed spreading further
• 8 for managing it in the longterm.
Do not use a persistent herbicide.
Combined treatmentRefer to Sections:
• 3.4, but also consider Section 4 and 5 options
• 8 for managing Japanese knotweed in the long term. Soil only suitable for reusing on site.
Refer to Sections:
• 2.3 on how to avoid contaminating the site again
• 8.5 if Japanese knotweed is growing near the site.
Herbicide/barrierRefer to Sections:
• 2 to avoid spreading further.
• 3 for treatment
• 4 for containing Japanese knotweed using root barrier membrane, if necessary
Off-site disposalRefer to Sections:
• 6 for guidance on disposal and Appendix I for guidance on removing rhizomes
• 7 for moving soil
• 2 to avoid Japanese knotweed spreading further
• 8 for managing it in the long term. Do not use a persistent herbicide.
YES
YES
YES
NO
NO
NO
NO
YES
HowdoIpreventJapaneseknotweedspreading?
i) youhaveaJapaneseknotweedmanagement plan(seesection3.1);
ii) allstaffareawareofwhatJapaneseknotweed lookslikeandwhattheirresponsibilitiesare;
iii) youhaveaclerkofworksresponsibleforthe managementofJapaneseknotweed.
2.1 Avoiding contamination around the siteItisessentialthatyoufindouthowmuchJapaneseknotweedinfestationthereisonthesiteandthateveryoneworkingthereclearlyunderstandsthis.Youshouldbriefallcontractorsfully.YoushouldrecordanyareasthatarecontaminatedwithJapaneseknotweedintheJapaneseknotweedmanagementplan(AppendixVandVI),isolatethemwithfencingandputuparestrictedaccesssign(AppendixVII).Section7describestheprecautionsyouneedtotakewhenmovingsoilinfestedwithJapaneseknotweed.
2.2 Good site hygieneTomaintaingoodsitehygiene,wesuggest:
a) asageneralrule,theareaofinfestationis7m horizontallyfromthenearestgrowthof Japaneseknotweedthatcanbeseen.To determineexactlyhowfartherhizomeshave spread,youwouldneedtodigaseriesoftest pitsandexaminethemcarefully;
b) afencethatcanclearlybeseenshouldmarkout theareaofinfestation.Signsshouldwarn peopleworkingtherethatthereisJapanese knotweedcontamination(appendixVII);
c) youshouldindicatestockpilesofsoil contaminatedwithJapaneseknotweedwith appropriatesignsandisolatethem;
d) youshouldnotusevehicleswithcaterpillar trackswithintheinfestedarea;
e) vehiclesleavingtheareashouldeitherbe confinedtohaulageroutesprotectedbyroot barriermembranes,orbepressurewashed (seesection7.1);
f) vehiclesusedtotransportinfestedsoilsmust bethoroughlypressure-washedinadesignated wash-downareabeforebeingusedfor otherwork;
g) areasinfestedbyJapaneseknotweedthatare notgoingtobeexcavatedshouldbeprotected byrootbarriermembraneiftheyarelikelytobe disturbedbyvehicles(seesection4).Root barriermembraneswillneedtobeprotected fromdamagebyvehicleswithalayerofsand aboveandbelowtherootbarriermembrane, toppedwithalayerofhardcoreorothersuitable materialasspecifiedbyanarchitect orengineer(seesection7.1);
h) thematerialleftafterthevehicleshavebeen pressurewashedmustbecontained,collected anddisposedofalongwiththeotherJapanese knotweedmaterial;
i) aclerkofworksshouldoverseetheJapanese knotweedmanagementplan(appendixV), includingtheprovisionsforavoiding contamination.Everyoneworkingonsitemust clearlyunderstandtheroleandauthorityofthe clerkofworks.
12 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites13
HowdoImanagemyJapaneseknotweedproblem?3.1 Japanese knotweed management plansOnceyoufindJapaneseknotweedonasite,itisessentialthatyousetupsomeformofJapaneseknotweedmanagementplan(KMP).Youneedtoidentifyaclerkofworkstooverseetheplanandyouneedtoletallrelevantcontractorsonthesiteknowhowimportanttheplanis,forexamplethrough‘toolbox’briefingstostaffoperatingonthesite.
ItisimportanttoonlydisturbaminimumamountofJapaneseknotweed.Itisvitalthatyoukeepthiscontaminatedmaterialseparatefromotherwasteandsurplussoilwithinthesite.SoilfreefromJapaneseknotweedandotherwastemaybedisposedofrelativelycheaplyunderexemptionsfromwastelicence.UnlessanareaofJapaneseknotweedislikelytohaveadirectimpactonthedevelopment,youshouldcontrolitinitsoriginallocationwithherbicideoverasuitableperiodoftime,usuallytwo-fiveyears.
AppendixVgivesatemplateofaKMPforreference.Youcanchangethisaccordingtoyourownneeds.AppendixVIgivesanexampleofacompletedKMP.
TheKMPisanimportantdocumentandprovidesavaluablerecordofthetreatmentofthesiteforfutureowners.ItmayalsoprovideevidencethatthesitehasbeenappropriatelymanagedifsubsequentJapaneseknotweedregrowthresultsinlitigationagainstthecontractor.
3.2 Herbicide treatmentItisessentialthatacompetentandqualifiedpersoncarriesouttheherbicidetreatment.ContractorsmusthavetheappropriateNationalProficiencyTestsCouncil(NPTC)certification.Theymustcarefullyfollowtheinstructionsontheherbicidelabel.Youcanonlyusecertainherbicidesinornearwater,andyouneedapprovalfromusbeforeyoucanusethese.
ThemosteffectivetimetoapplyglyphosateisfromJulytoSeptember(orbeforecoldweathercausesleavestodiscolourandfall).Springtreatmentisacceptable,butlesseffective.Triclopyr,picloramand2,4-Daminecanbeusedthroughoutthegrowingseason.Youshouldavoidthefloweringperiodtoprotectbeesandotherpollinatinginsects.Themajorityofherbicidesarenoteffectiveduringthewinterdormantstagebecausetheyrequirelivingfoliagetotakeuptheactiveingredient.Anexceptiontothisruleispicloram,whichcanbeappliedasasoiltreatment.
Rhizomecanremaindormantforaconsiderableperiodafterregrowthhasapparentlystopped,andsoyouneedtocheckifrhizomesarestilllivingbeforedisturbingthesite.Unconfirmedobservationssuggestrhizomecanstayaliveformorethan20years.However,treatingJapaneseknotweedwithanappropriateherbicidecanreduceitsgrowth,evenifitwereonlytreatedafewweeksbeforeitwasdisturbed.IfthetimescaleofthedevelopmentdoesnotgiveyouenoughtimetoeffectivelyeradicateJapaneseknotweedusingchemicals,youshouldstilltreattheplant,ifitisinleaf,assoonaspossible.
YoushouldexpecttouseherbicidetreatmentforatleastthreeyearsbeforeJapaneseknotweedstopsgrowingback.ItisimportanttorememberthatyoucannotrelyjustonherbicidetogetridofJapaneseknotweed.YoumustnotseethelackofregrowthasevidencethattheJapaneseknotweedisnolongeralive.Disruptingtherhizomebydisturbingthesoilislikelytoresultinsubstantialregrowth.
2.3 Avoiding new contamination to the siteThisadviceisparticularlyrelevanttositesfortunateenoughnottobeinfestedbyJapaneseknotweed.
Thethreemostcommonwaysasitecanbecomeinfectedare:
Infestedtopsoil:TherehavebeennumerousincidenceswheresiteownershavepaidtoremoveJapaneseknotweedinfestedsoilfromtheirsite,onlytointroduceitagainwithtopsoiltheyhaveboughtandnotinspected.
SectionN.6.4.5ofBS3882:1994,theBritishStandardfortopsoilclearlystatesthatitiscriticalthatmaterialshouldbefreefromJapaneseknotweedpropagules,rhizomeandvegetativefragments.Youshouldalwaysinspecttopsoilbroughtintothesite,usingtheguidanceinappendixI-IVofthiscode.Youcanoftengettopsoilfromdifferentsources.Ideally,youshouldinspectthesesourcesbeforeyoureceivematerialonsite.Youshouldusetopsoilfromdifferentsourceswithindistinctareasofthesiteandkeeparecordofthis.Thismayhelpyouwithcompensationclaimsagainstthesupplier,shouldJapaneseknotweedsubsequentlygrow.Ifyouhaveanyevidencethatsub-standardtopsoilisbeingsold,youshouldletthelocalTradingStandardsOfficeknow.
Contaminationonvehicles:Youshouldinspectvehiclesbeforeusingthemonsite.Youneedtopayparticularattentiontocaterpillartracksandwheretrucksanddumpersarestowed.
Fly-tipping:MostJapaneseknotweedinfestationsondevelopmentsitesstartedasaresultoffly-tippedwasteandthisoftencontinuesafterthedevelopmenthasstarted.
Youshouldreportanyfly-tipping
incidencestousonthe24-hour
freephonenumber0800807060.
2.4 Reusing treated soils on site IfsoilhasbeentreatedandisfreefromJapaneseknotweedcontaminationandsuitableforuse,itcanbereusedonsitewithouttheneedforawastemanagementlicenceoranexemption.Iftakenoffsite,thismaterialmustbedisposedofinalandfill.
Developersreusetreatedsoilsattheirownrisk,unlesstheagreementtheyhavewiththeircontractorsstatesotherwise.Tominimisethepotentialproblemstherecouldbeifthesoilwasnottreatedadequately,youshouldonlyusesoilagainwherethereislittleriskofspreadingJapaneseknotweed.Thesiteshouldalsofacilitateherbicidetreatment,ifitisnecessary.Suitableareasshouldbeawayfrom:
a) watercourses(weadvise,atleast50m) andditches;
b) beingdisturbedbypeopleorlivestock;
c) existingamenityareas,lawnsandgardens;
d) boundarieswithotherproperties;
e) anareathatcouldbedisturbedinthefuture.
Youshouldalsousethesoilinarestrictedarea,ratherthanspreadoutacrossthesite.YoushouldrecordthisareaintheJapaneseknotweedmanagementplanandkeeparecordofinspection.Youmusttreatanyregrowthappropriately.
HowdoIpreventJapaneseknotweedspreading?
Sub-lethal glyphosate ‘bonsai’ regrowth
First yearregrowth after glyphosate
14 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites15
Thereisincreasingconcernaboutusingpesticides.Itisimportantthatsuitablyqualifiedoperatorsusethesechemicalsappropriately.Whenyouuseaherbicide,alwaysfollowtheinformationonthelabel.Themostimportantquestionstoaskbeforedecidingwhichherbicidetouseare:
3.3.4: What should I use if I intend to bury the material or dispose of it off-site?Ifyouintendtoburythematerialordisposeofitoff-site,youshouldonlyuseglyphosateformulations.Iftherearepersistentherbicidespresent,thiswillpreventyoufromusingburialasaJapaneseknotweeddisposaloption(seesection5.4).Refertopage6-7fordetailsoftherelevantwasteregulation.Ifsentfordisposaloff-site,therequirementsoftheEPA1990s.34andtheDutyofCareRegulationswillhavetobecompliedwithinrelationtothetransferofthewaste.Usingcertaintypesorquantitiesofpesticidecouldmeanthatsoilorplantmaterialisclassifiedas‘hazardouswaste’,andthenyouwouldneedtodisposeofitatahazardouswastelandfill.ItwouldalsohavetobeconsignedandsuitablydescribedundertheHWR2005,whichwouldincludegivingadescriptionofthepesticide.
WeadvisedeveloperstoseektheadviceofasuitablyqualifiedpesticideoperatororBASISregisteredpesticidesadvisorbeforetheystartasprayingprogramme.
Therearesomepracticesthatyoucanfollowtofurtherreducethechanceofdamagingengineeredstructures.Earlyresults(currentlyunpublished)suggestthattheresidualherbicideTordon22K,containingpicloramasanactiveingredient,achievesahighlevelofJapaneseknotweedcontrolwhenapplieddirecttofoliageorasasoiltreatment(5.6l/ha).
Itisadvisabletoconsidersoiltreatment,oraneffectiverootbarriermembranemethodbeforecreatinganengineeredsurfaceoveranyareathatcouldsupportlivingJapaneseknotweedrhizome.Thisisparticularlyimportantundertarmac,whichcanbedamagedconsiderablybyJapaneseknotweed.
Itisimportantthatyouuseherbicidesasstatedonthelabels.ItisnotappropriatetouseTordon22Knearwaterortrees,wheretheextensiverootsystemcantakeuptheherbicidefromthesoil.
Only qualified operators should use herbicides and they must follow the instructions on the label when using them.
FurtherguidanceisalsoavailableintheformerWelshDevelopmentAgencyguidelines,nowWelshAssemblyGovernment,detailofwhichisgiveninsection9.2.TheseguidelinesshouldbeusedinconjunctionwiththiscodeinWales.
Herbicide Affects grasses?
Time of application Approved for use in or near water?
Persistency
Glyphosate Yes May-October(lateseasonpreferable)
Yes(certainformulations)
Non-persistent
2,4-DAmine
Triclopyr
Picloram No Allyear(soiltreatmentinwinter)
No Upto2years
No May-October(earlyseasonpreferable)
No Upto6weeks
No May-October(earlyseasonpreferable)
Yes(certainformulations)
Upto1month
3.3 Which herbicide should I use?
3.3.1: Is the site in or near water?‘Inornearwater’includes‘drainagechannels,streams,riversponds,lakes,reservoirs,canalsanddryditches’.Italsocoverscontrolofvegetationgrowingonbanksorareasimmediatelyadjacenttowaterbodies.Ifyouintendtouseaherbicidewithin5mofwater,orifyourtreatmentmayimpactwaterquality,youshouldcontactusbeforehand.
Whereverthereisariskofcontaminatingawatercourse,choiceofherbicidesislimitedtoformulationsofglyphosateand2,4-Daminethatareapprovedforusenearwater.Notallherbicidesthatcontaintheseactiveingredientsaresuitabletouseinornearwater.Youmustrefertothelabeltomakesurethattheproductyouintendtouseisapprovedforuseinornearwater.Youmustconsultusbeforeyouuseaherbicideinornearwater.YouwillneedtodiscussthetreatmentwithaBASIS1qualifiedofficerfromthelocalAreaoffice.Youcangetthetelephonenumberofyourlocalofficebycallingournationalcallcentreon08708506506.YoumayneedtocompleteaWQM1notificationform.Youshouldallowustwoweekstoprocessthisapplication.
3.3.2: Will the treatment damage trees or grass, which I wish to keep?Glyphosateisanon-selectiveherbicideandthereforekillsmostplants,includinggrass.Youcanuseit,withcare,aroundmaturetreesandshrubs.Picloramand2,4-Damineareselectiveandyoucanusethemwithoutharminggrass.Picloram
ispersistentinsoil,pronetoleachingandhighlydamagingtonearbytrees.
3.3.3: If I want to reuse the soil from the treated area for replanting, how long before I am able to landscape it?Ifyouwanttocarryonusingsoiloryouwanttoreuseitimmediatelyforlandscaping,itwouldbeappropriatetouseanon-residualherbicide,suchasglyphosate.Ifreplantingislikelytobedelayedforatleastsixweeks,youmayconsideraformulationcontainingtriclopyr.Ifyouintendtocovertheareainahardsurface,ordelayreplantingforatleasttwoyears,apersistentchemical,suchaspicloram,wouldbeappropriateifyouuseitawayfromtreesandwatercourses.Itisnotacceptabletoburysoiltreatedwitharesidualherbicideifitmaycontaminategroundwater.However,ahardsurfacecanusuallybelaidovertreatedsoilwithoutcausingpollution.
Itishighlyunlikelythatasingletreatmentofherbicidewouldprovideenoughcontroltoletyousafelyreusethesoilforlandscapingpurposes.Wheneveryoureusesoil,youshoulduseitinalocalisedarearatherthanspreadacrossthewholesite.Weadvisethatyoushouldnotuseitwithin50mofawatercourse.Youshouldchooseasitethatcaneasilybeinspectedandsubsequentlytreated,ifJapaneseknotweedregrows,asdescribedinSection2.4(Reusingtreatedsoilsonsite).
Post-treatment reaction to picloram
Regrowth after picloram treatment
16 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites17
BASIS1 is an organisation committed to making sure people involved in handling and using pesticides are competent. BASIS maintain a register of trained advisors, who need to demonstrate an annual programme of continual professional development to maintain their qualification. Details on the BASIS Professional Register are available from 34, St John Street, Ashbourne, Derbyshire DE6 1GH. Tel: 01335 343945.
Arootbarriermembranephysicallyprotectsastructureorcleansoil.Itmustbemadeofamaterialthatisfitforpurpose.Itshouldbemadeofamaterialthatcanbe:
a) usedwithoutdamage;
b) providedinlargesizes,tominimisetheneed forseals;
c) sealedsecurely;
d) remainintactforatleast50years;
e) resistUVdamageifitisexposedtosunlight.
VariousrootbarriermembranesareavailablewhichclaimtopreventJapaneseknotweedpenetrating.Arootbarriermembraneisonlyasgoodasthewayinwhichithasbeenlaid.Itisessentialthatthereisexpertsupervisionwhentherootbarriermembraneissupplied.
Japaneseknotweedwilltendtobreakthroughholesorjoinsinthefabric,soitisessentialthattheintegrityoftherootbarriermembraneismaintained,andthereisaminimumnumberofseams.Ideally,rootbarriermembranematerialshouldconsistofasinglesheet.
Youmustensurethatrootbarriermembranescontainingleachablechemicalsdonotpollutestreamsandgroundwater.
GiventhatJapaneseknotweedrhizomemayremaindormantforatleast20years,itisimportantthatarootbarriermembranecarriesaguaranteewellbeyondthattime.Weadviseamanufacturer’sguaranteeofatleast50years.
Rootbarriermembranesarevulnerabletodamagefromburrowingmammals.Buryingrootbarriermembranecells2mordeepershouldprovidesomeprotectionagainstsmallermammals,suchasrats.Ifbadgersandrabbitsarepresent,youshouldconsiderdeeperburial.Badgersandtheirsettsareprotectedbylawandshouldnotbedisturbed.
Root barrier membranes are currently used in a number of ways:
• Cell formation
• Protecting structures and hard surfaces
• Preventing horizontal spread
• Protecting services, etc.
3.4 Combined treatment methodsSitetrialshaveshownthatcombiningdiggingandsprayingtreatmentiseffectiveinreducingthetimeneededforchemicalcontrol.Youneedtotakegreatcarewiththismethodtoavoidspreadingplantmaterial.
Theaimofthetreatmentistobreakuptherhizome,whichstimulatesleafproductionandthereforemakestheplantmorevulnerabletoherbicidetreatment.Rhizomeisalsostimulatedtoproducegreengrowthifitisnearoronthesurface.Thereforethesuccessofthetreatmentwillbedeterminedbytheamountofrhizomethatisbroughttothesurfacelayer.
Youshouldcut,dryandburnJapaneseknotweedcaneson-siteifallowed(seeSection5.2).Youcanalsoburncrownsandsurfacerhizomerakedfromthesurfacewithtinesortakethemtolandfill.Youcannotrelyonburningtokillrhizomeorcrowns.
ThemajorityofJapaneseknotweedrhizomeexistsintheupperlayersoftopsoil.Ithasbeenestimatedthatinaninfestedarea,14,000kg/hadryweightofJapaneseknotweedmayexistinthetop25cm(Brock,1994).Youmayuseanexcavatortoscrapesurfacecrownsandrhizomesintoapile.Youcanthencultivatetheexposedgroundtoatleast50cmdeep,dependingonhowdeepthebulkoftherhizomeis,andturnthepiledmaterialandre-spreaditoverthecultivatedarea.
Thisprocessstimulatestherhizometoproduceahigherdensityofstems,whichmakesitmorevulnerabletoherbicidetreatment.Wehaveseenthatsubsequentherbicidetreatmenthasachievedsignificantlybetterratesofcontrol.WhilstthisdisturbancetechniquemayhavethepotentialtoeradicateJapaneseknotweedinfestations,itcannotguaranteeit.Itwouldbeinappropriatetodisposeoftreatedmaterialunderawasteexemption.Youcouldreusesoilon-site,inlocalisedareasthatwouldfacilitateherbicidetreatmentifregrowthweretooccur(seesection2.4).
Youcandigthesoilduringthewinter,ifyoutakecarenottocompactwetsoil,andyoucantreatregrowthduringthespringandsummer.Soilcanbecomecompactedifyoudriveoveritorworkitwhenit’swet.Thisreducesrainwaterinfiltration,whichincreasesrunoffandmayspreadJapaneseknotweedacrossthesiteandintowatercourses.Compactedsoilsarealsolesslikelytoencouragetheregrowthneededfortreatment.
YoumusttakeextremecaretomakesurethatallequipmentusedonsiteisfreeofJapaneseknotweedmaterialbeforeleavingthesitetoavoidcontraveningtheWildlife&CountrysideAct,1981.Toreducetheriskofcontaminatingvehicles,youshouldavoidexcavatorswithcaterpillartracksandthoroughlypressure-washvehiclesafteruseorbeforeleavingsite(seesections2and6.2).
HowdoIuserootbarriermembranes?VariousrootbarriermembranesareavailablewhichclaimtopreventJapanese
knotweedpenetrating.Arootbarriermembraneisonlyasgoodasthewayinwhich
ithasbeenlaid.Itisessentialthatthereisexpertsupervisionwhentherootbarrier
membraneissupplied.
18 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites19
The importance of intact root barrier membrane
4.1. Cell formation InsomesituationswhereburialisthepreferreddisposalmethodbutitisnotpossibletoburyJapaneseknotweedto5m(seesection5.4),itmaybecompletelyencapsulatedintoarootbarriermembranecell.Thesecellsmaybeplacedunderbuildings,withincellarvoidsorinplacesthatwillnotbedisturbed.Itisimportantthatthedeedsofthepropertyshowwherethesecellsarelocated,toavoiddamageinthefuturethatcouldbecaused,forexample,bytrenchingtolayservices.Toavoid
damageafterithasbeeninstalled,theupper‘cell’surfacemustbecoveredwithacappinglayer,atleast2mdeep.Dependingwhereitislocated,thecellisquiteoftenusedinthelandscapeandtreesplantedwithinthecappinglayer.
Youmustuserootbarriermembranes
inawaythatwillnotincreasetheriskof
subsidencetosubsequentbuildings.
Cell formation - putting the Dendro-Scott root barrier membrane in place
Stage 1: Calculatevolumerequiredandexcavate
site,allowingfor2mdepthofburial
Stage 2: Protecttheintegrityoftherootbarrier
membranewithalayerofsandandprovideshutterply
supportsfortheedgeofthecell.
Stage 3: Putrootbarriermembraneinplace,allowing
enoughmaterialalongtheedgestoeventuallyprovide
aseal.
Stage 4: Protecttherootbarriermembranefromtyre
damagewithalayerofsand.
Cell formation - putting the Dendro-Scott root barrier membrane in place
Stage 5: Fillthecellwiththeknotweedinfestedsoil.
Noothermaterial,contaminants,orwastesshouldbe
included.
Stage 6: Makesurethatdedicatedvehiclesareused
andcleanedproperlyaftertheyhavebeenused.
Haulageroutesmustbeprotected.
Stage 7: Putthesurfaceoftherootbarriermembrane
inplaceandmakesurethecellisadequatelysealed.
Stage 8: Protectthesurfaceofthecellwithsandand
burydeepenoughtopreventdisruptioninthefuture.
Itisimportantthatthesuppliersofrootbarriermembranescanadvisethedesigning
architectofpotentialproblemsandsuperviseinstallation.
20 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites21
4.2 Protecting structures and hard surfaces WherethereisachancethatJapaneseknotweedrhizomeisstilllivingwithinthesoilandthereareplanstoconstructbuildingsintheseareas,thereareanumberofwaysrootbarriermembranesareused:
1. Beforedevelopment,infestedareasaresealed horizontallywiththerootbarriermembrane. Caremustbetakenthatlayingtherootbarrier membranedoesnotaffecttheconditionofthe buildingorstructure,especiallyonsloping ground.
2. Rootbarriermembranesarebuiltintothe structurestopreventJapaneseknotweed enteringthebuildingorlaidhorizontally underneaththepavedsurface,roadorcarpark.
AsJapaneseknotweedcouldcreate
‘heave’andcauseinitialfracturesto
concretefloorsorapavedsurface,it
isimportantthatapliablesurfaceis
laidbetweentheconcreteandtheroot
barriermembrane.Thiswouldallowthe
Japaneseknotweedtogrowwithout
stressingtheconcrete.Caremustalso
betakentoprotecttheservicesentering
thebuilding.
Surface sealing - putting the Dendro-Scott root barrier membrane in place
Stage 1: Protecttheintegrityoftherootbarrier
membraneandpreventdamagefrom‘heave’witha
layerofsand.
Stage 2: Puttherootbarriermembraneinplace.
Stage 3: Applyanotherlayerofsandoverthesurface
oftherootbarriermembrane.
Stage 4: Layfinalfloorsurface.
Surface sealing - peripheral protection
Make sure the root barrier membrane is sealed properly around pillars and other structures.
22 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites23
4.3 Preventing horizontal spread
Preventing horizontal spread by using a vertical root barrier membrane
Stage 1: Excavateatrench,makingsurethatallthe
knotweediscontained.
Stage 2: Puttherootbarriermembraneinplace.
Stage 3: Supporttherootbarriermembranewith
shutterplyandbackfillthetrench.
Stage 4: Makesurethatthepresenceoftheroot
barriermembraneisrecordedandisnotdisruptedby
futuredevelopmentsandlandscaping.
4.4 Protecting services, etc Ifservicesorothersmall-scalestructuresneedtobeconstructedinareasinfestedwithJapaneseknotweed,itisoftenmorecost-effectivetoprotecttheintegrityofthestructurewithinarootbarriermembraneratherthansubjecttheentireareatoafull-scaleJapaneseknotweedmanagementplan.Itisessentialthatanysoilcontainedbytherootbarriermembrane,inproximitytothedrainorstructure,isfreefromknotweed.Thesurroundinginfestationcanthenbecontrolledusingherbicidesoveraperiodoftime.
CarefullyusingaverticalrootbarriermembranehasbeenusedtopreventthehorizontalgrowthofJapaneseknotweed.Thisisusuallyusedagainstuncontrolledinfestationsfromneighbouringproperties.Verticalrootbarriermembranesarealsooftenusedaroundtheedgeofcuts,asaprecaution
againstregrowthfromanyresidualrhizome.Verticalrootbarriermembranescanoftenbemostconvenientlyusedwhenreinforcedbyaplywoodframe.Ifitisnotknownhowdeeptherhizomehasspread,verticalrootbarriermembranesshouldbeusedto3mdeepasastandard.
HowdoItreatordisposeofJapaneseknotweedonsite?Whereverpossible,youshouldkeeptheamountofJapaneseknotweedexcavatedto
aminimumandfocusontreatingtheJapaneseknotweedinitsoriginallocationand
protectingengineeredsurfacesandstructuresfrombeingdamaged.Ifyouwishto
treatJapaneseknotweedinitsoriginalposition,seeSection3,4.2,4.3and4.4.
5.1 Cutting Japanese knotweed canesPulledstemsoftenhavethehighlyinvasivecrownmaterialattachedtothem,andmustbedisposedofinthesamewayasrhizome.Cutstemsarelessofarisk,andaresafeoncetheyhavedriedoutandturnedbrown.Ifyouintendtotreatregrowthwithaherbicide,youshouldremovecutmaterialfromthetreatmentareatoallowthespraytoeffectivelycoverthenewgrowth.
Youshouldleavecutstemswheretheycandryout.Japaneseknotweedcangrowagainfromjustsmallpiecesofstem,soyoushouldleavedryingcanesonanappropriatemembranesurface,notonsoilorgrass.Oncethestemshavedriedtoadeepbrowncolourtheyaredead.Thisisnotthecasewithcrownorrhizomematerial.Japaneseknotweedstemscanbeleftonsiteaftercuttingif:
• the stem is big enough that it won’t be blown away by wind or traffic; • there is no risk they can get into a watercourse;• the stem has been neatly cut near its base using a cutter, hook or scythe.
Youshouldcutstemscleanlysothattheydon’tcreatepiecesofstemthatmayspreadandregrow.Youshouldnotuseflails.ItisgoodpracticetochemicallytreatJapaneseknotweed,ratherthancontinuouslycuttheregrowth.
5.2BurningYoucanusecontrolledburningofstem,rhizomeandcrownmaterialaspartoftheprogrammetocontrolJapaneseknotweed.Thismeansthematerialislesslikelytosurviveandthereislessmaterialtoburyordisposeofoff-site.Initsnativearea,Japaneseknotweedgrowsonvolcanicashandaroundhotfumaroles,sodon’trelyonheattreatmenttocompletelykillit.Burningmusttakeintoaccountanylocalby-lawsandthepotentialtocauseanuisanceorpollution.YoushouldcontacttheEnvironmental
HealthOfficeoftherelevantlocalcouncilbeforeburning.YoumustinformourlocalAreaofficeEnvironmentManagementTeam(08708506506)atleastoneweekbeforeanyburialorburningactivity.
YoumaycarryoutburningintheopeninaccordancewitharegisteredexemptionasdescribedinParagraph30ofSchedule3oftheWMLR1994.ThisexemptionmustberegisteredwiththeEnvironmentAgencyandcovers“burningwasteonlandintheopenif…..[it]consistsofplanttissue”.TofallunderParagraph30thewastemustbeburnedonthelandwhereitwasproducedandthetotalquantityburnedinanyperiodof24hoursdoesnotexceed10tonnes.Theexemptionalsocoversassociatedstorage,whichwillallowthematerialtodry,whichitislikelytoneedbeforeitcanbeburned.
YoumustinformourlocalAreaoffice
EnvironmentManagementTeam
(08708506506)atleastoneweek
beforetheburning.
24 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites25
5.3 ExcavationWhereverpossible,youshouldtreatJapaneseknotweedinitsoriginallocation.YoushouldonlyconsiderexcavatingJapaneseknotweedasalastresort,unlessthisispartofanon-sitetreatmentmethod.Ifyouuseexcavationforoff-sitedisposal,youmusttakegreatcaretoavoidexcesswasteandmakesuretheexcavatedJapaneseknotweeddoesnotcontaminatesurplussoilthatiscurrentlyfreefrominfestation.
Itisimportanttocarefullyidentifyrhizomesduringtheexcavationprocess.Someexcavationshavebeen6metresdeepbecauseofmis-identifiedtreeroots!Arecentinfestationmayhavealimitedrhizomesystemthatisshallowandonlyextendsashortdistance.IfJapaneseknotweednaturallyspreadsontonewground,orisdumpedonthesurface,rhizomerarelypenetratesdeeperthan3m.However,ifJapaneseknotweedwasdumpedintheearlystagesofalongperiodofwastetippingitmayhavebecomeburiedbyotherdepositedwasteandbedeeperthan3m.AppendicesI-IVgiveguidanceonrecognisingrhizomes,includingcomparisonswithotherplantmaterialoftenfoundondevelopmentsites.Sectionv)ofAppendixIalsodescribeshowtoexcavateJapaneseknotweedbeforeburyingorbundingit.Theguideisdesignedasafieldreferenceduringexcavations.
Soilcanbecomecompactedifdrivenoverorworkedwhenwet.Thisreducesrainwaterinfiltration,whichincreasesrunoffandmayspreadJapaneseknotweedacrossthesiteandintowatercourses.Compactedbundsarealsolesslikelytoencouragetheregrowthrequiredfortreatment(seesection5.5).
5.4 The burial methodSoilcontainingJapaneseknotweedmaterialandburntremainsofJapaneseknotweedmaybeburiedonthesitewhereitisproducedtoensurethatyoucompletelykillit.Itisadvisabletoapplyanon-persistentherbicideatleastoncetoreducethegrowthofinfectivematerial.Itisimportantthatanon-persistentherbicideisused,suchasglyphosate,becausepersistentchemicalswillcontaminatethematerialforawhile.Theperiodoftimeduringwhichtheherbicideis‘active’isdescribedontheproductlabel.Materialcannotbeburiedduringthatperiodofactivity.Buryingmaterialtreatedwithapersistentherbicidemaycontaminategroundwater.Ifyouareindoubtwhethertheherbicideisstillactive,youshouldconsultwiththesupplieroftheproductorthecontractorwhoappliedit.
Youmustburymaterialon-siteatleast5mdeep,unlessyouaredoingthisinaccordancewithsection4.1.YoushouldthencovertheJapaneseknotweedmaterialwitharootbarriermembranelayer(seesection4)beforeinfillingitto5mdeepwithinertfillortopsoil.RootbarriermembranesthatmayhavebeenusedtoprotectcleangroundfromvehiclesinvolvedinexcavatingJapaneseknotweedcanalsobeburied.ThismethodreliesonthedepthofburialasthemainJapaneseknotweedtreatment,ratherthantheprotectionfromtherootbarriermembrane.Ifmaterialcannotbeburieddeepenough,themethoddescribedinparagraph4.1.mustbeused.
Whereyouuseon-siteburial,westronglyadvisethatyouaccuratelymapandrecordthelocationoftheburialsitetopreventpotentialdisturbanceandre-infestation,andthatyouadviseanyfutureownersofitsposition.Japaneseknotweedislikelytosurviveformanyyears,dependingonhoweffectivethetreatmentwasbeforeitwasburied.Itisessentialthatyoudonotburyitwherelandscaping,installingservices,erosionfromawatercourseorsubsequentdevelopmentwilldisturbit.
YoumustinformourlocalAreaofficeEnvironmentManagementTeam(08708506506)atleastoneweekbeforetheburial.Wewilltheninspectandinformyouwhetherwearesatisfiedthatthematerialcanbeburied.ItisonlyacceptabletoburyJapaneseknotweedmaterialifthesoilisotherwiseuncontaminated.Anyotherwaste,suchasrubbleordiscardedhouseholditems,mustbeseparatedandremovedduringexcavation.Ifcontaminantscannotbeseparated,itcannotbeburied.Ifburialresultsinpollutionorharmtohealthyouwillnothavecompliedwithyourwaste‘relevantobjectives’(seepage6-7)andmayfaceprosecution.
5.4.1 Stockpiling Japanese knotweed infestedsoil prior to burialIfsoilcontainingJapaneseknotweedisstockpiled,thematerialmustbestoredinamannerthatwillnotharmhealthortheenvironment.Thestockpileshouldbeonanareaofthesitethatwillremainundisturbed.Youshouldclearlysignthisarea(appendixVII).YoushouldregularlytreatJapaneseknotweedregrowthwithherbicidetoavoidre-infestation.Asaprecaution,youshouldlaythestockpiledmaterialonarootbarriermembranetoavoidcontaminatingthesitefurther.
5.5 The bund methodWherelocalconditionsmeanyoucannotuseburialasanoption,itmaybepossibletocreateaJapaneseknotweedbund.AbundisashallowareaofJapaneseknotweed-contaminatedsoil,typically0.5mdeep.Thebundcaneitherberaised,ontopoftheground,orplacedwithinanexcavationtomakethesurfaceflushwiththesurroundingarea.ThepurposeofthebundistomovetheJapaneseknotweedtoanareaofthesitethatisnotused.This‘buystime’fortreatmentthatwouldnotbepossiblewheretheJapaneseknotweedwasoriginallylocated.
Thewayyouconstructthebundiscritical,especiallyifitislikelytobedeeperthan0.5m.Theaimistoconcentratetherhizomeintotheuppersurfaceofthebund,whereitwillgrowandbecontrolledbyherbicide.Ifrhizomeisburieddeep,itwillbecomedormantwheninsidethebundandregrowwhentheapparentlycleansoilisusedforlandscapingonthesite.
Itisbesttothinkaboutifyouwillneeda
bundwhenyouarepurchasingthesite,
andplanningthebuildingphases.Abund
needsthefollowing:
a) anareasetasideforatleast18months-2years forJapaneseknotweedtreatment.Deeperbunds mayneedlonger;
b) localplanningauthorityapproval,ifnecessary, beforecreatingabund.Itisadvisableto emphasisethepurposeofthebund,andhow longitisexpectedtotaketobuildwhen discussingtheproposal;
c) anareawithintheperimeteroftheoriginalsite. RemovingJapaneseknotweedcontaminatedsoil fromasitewillneedawastelicenceanddisposal willonlybepermittedatlicensedlandfillsites;
d) positionedawayfromwatercourses(weadviseat least50m)andtrees.Ifthebundistobecreated onasitepreviouslyfreefromJapanese knotweed,cleantopsoilfromthebundareamay beremovedandusedforlandscapingpurposes, perhapsinrestoringthesitewhereJapanese knotweedwasexcavated;
e) temporarybundsshouldhavearootbarrier membranelayertoprotecttheunderlyingsite fromJapaneseknotweedinfestation.Permanent bundsonpreviouslyJapaneseknotweed-free areasshouldalsousearootbarriermembrane layertocontainthematerial.Ifthesitewas previouslycontaminatedwithJapanese knotweed,thereisnoneedfortherootbarrier membranelayer;
f) notmorethan1mdeep,andpreferablyno deeperthan0.5m.Clearly,alargeareamay beneededtoprovideenoughspaceforabund, especiallyifinfestationsarescatteredaround thesiteordominatealargepartofit.
26 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites27
Pre-excavation treatmentYoushouldtreattheJapaneseknotweedinfestationwithaherbicidebeforeremovingit.Becausematerialisnotintendedforburialorremovaloff-site,youcanconsidersuitablepersistentherbicides.But,itisimportanttoconsiderwhatwillhappentothematerialwhenyouchooseaproduct.Itwouldnotbeappropriatetouseaherbicidewithatwo-yearresidualactivityifyouintendtousethesoilforlandscapingafteraone-yearbundingprocess.
Whenyouhaveallowedenoughtimefortheherbicidetotakeeffect(preferablyatleastafortnight)youshouldcutandremovethecanes.Afterithasdriedout,youcanburnthismaterial,followingtherestrictionsalreadydescribed(seesection5.2).Youshouldeventuallyplaceanyunburnedmaterial,especiallyfromthebaseofcanes,ontopofthebund.
Youshouldrakethesurfaceofthesitewithtinesandcollectthecrownsandsurfacematerial.Themajorityofrhizomeisshallow,andcareatthisstagecanisolatemuchofthemostinfectivematerial.Ifthesoilissandyandnotheavilycontaminatedwithstonesorsolidwaste,youcanuseextendedtinestorakerhizometothesurface.Youcanplacethismaterialontopofthedriedcanesbeforeburning,orspreaditontopofthecompletedbund.Burningthismaterialbeforeplacingitonthesurfaceofthebunddestroyssomerhizomeandisthepreferredoption,butyoumustmakesurethatyouclearthefiresiteofallrhizomeandcrownmaterialandthatfiresareallowedatthesite(seesection5.2).
Refertosectionv)oftherhizomeidentificationguideforguidanceonexcavatingrhizome.Theexcavationshouldbeinspectedtomakesuretherearenolivingrhizomeleft.Theaimoftheexcavationistousetherelativelycleansubsoilasthebaseofthebundandconcentratetherhizome-richmaterialintothesurfacelayer.
Bund constructionAwell-constructedbundshouldhavethemajorityoftherhizomenearthesurface,whichwillencourageregrowth.Thebaseofthebundshouldbemadeupofthesubsoillayer,whichhasthelowestamountofrhizomeinit.Whenyouhavecreatedthebaseofthebund,youcanplacethetopsoiloveritandspreadthesurfacematerial,eitherburnedornot,overthesurface.
Youcanaddfertilisertothebundmaterialtohelpsubsequentregrowth.Thiswillincreaseleafareaandimproveherbicideuptake.Youshouldnotusefertilisernearwatercourses.
Treating regrowthThefragmentedrhizomesinthesurfacelayerarestimulatedtoproducenewgrowth.Afteroneortwoherbicidetreatments,furthersignificantregrowthisunlikely.Itishighlyadvisabletodisturbthebund,rakingpotentiallydormantrhizometothesurfaceandallowingthismaterialtoregrowbeforetreatingitwithherbicide,sothatyoucanbeconfidentthatthebundhasbeentreatedeffectively.
Itisparticularlyimportantwithdeeperbundstoconcentraterhizome-richsoilintothesurfacelayer,anddisturbthebundaftertreatment.
Thereisachoiceofherbicidefortreatingregrowthonthebund.Youmustthinkabouthowyouwilleventuallyusethebundmaterial.Ifyouaregoingtouseitforlandscapingaroundthesite,avoidherbicideswithaprotractedresidualactivity.Youmustreusetreatedsoilaccordingtosection2.4.
Itisimportanttorememberthatresearchhasshownthataslittleas0.7gofJapaneseknotweedrhizomemaygrowintoanewplant,andlargerpiecesofrhizomemayremaindormantforatleasttwentyyears.AcarefullyconstructedandmanagedbundisaneffectivewayoftreatingJapaneseknotweed,butitisnoguaranteeofgettingridoftheproblemcompletely.
HowdoIdisposeofJapaneseknotweedoff-site?6.1 Arrangements for landfillIfJapaneseknotweedcannotbekilledbyburyingorbundinginfestedexcavatedsoilonsite,youmustdisposeofitatasuitablylicensedorpermitteddisposalfacility.YoumustinformthesiteoperatorthatthereislivingJapaneseknotweedwithinthematerial.Youshouldregardthismethodasalastresort.DisposingofsoilcontaminatedwithJapaneseknotweedtolandfillusesupvaluablelandfillcapacity,involveslarge-scalehaulageandcanbeveryexpensive.
Landfillsareclassifiedasbeingfora)hazardous,b)non-hazardousandc)inertwastesandtheLandfill(EnglandandWales)Regulations2002asamendedsetoutwasteacceptancecriteriaforeachtypeoflandfill.WastesoilcontainingJapaneseknotweedisusuallyclassedascontrolledwastebutmaybehazardousifherbicideispresent.WhenevermaterialcontainingJapaneseknotweedisremovedtolandfill,itmustbetakentoasitewhichislicensedorpermittedtoreceiveit.NotalllandfilloperatorsmayagreetotakeJapaneseknotweed,andtheywillneedtohaveasuitableareatocorrectlyburyitin.
ItisgoodpracticetotreatJapaneseknotweedwithglyphosateatleasttwoweeksbeforeexcavatingit(seeSections3.2and3.3).Thiswillmakeanyrhizomethatmayhavebeenlostwhenitwasmoved,orleftbehindafteritwasexcavated,lesslikelytosurvive.Youshouldnotusepersistentherbicides.Thesearelikelytobestillactiveinthesoilwhenitisdisposedof,andmaymeanthesoilisclassifiedas‘hazardouswaste’asnotedabove.Thisislikelytoincreasethecostofhaulageanddisposal.
Ifyouuseoff-sitedisposal,takegreatcaretoavoidlosingmaterialenroute.Forsmallquantities,thismayinclude‘double-bagging’thewasteinheavydutywastebags.Forlargerquantitiesthatarebeingmovedinskipsortrailers,thiswillincludeliningandcoveringtheskipetc.withmembrane(SeeSection7).
Landfilloperatorsdealingwithmaterial
contaminatedwithJapaneseknotweed
mustmakesurethat:
a) theyarelicensed/permittedtoreceiveit;
b) theyhaveenoughcapacitytomakesurethey candealwiththematerialaccordingto thefollowing:
Material,includingcontaminatedsoils,
rhizomeandthecrownatthebaseofthe
stem,mustbeburied:
• atleast5metresdeep,(immediatelycoverto1-2 metres,finaldepthafter2-4weeks);
• atleast7metresfromthemarginsofthesite oranyengineeringfeatures,forexampledrains orbunds,ofthesite;
• atleast3metresabovethebase/linerof thelandfill.
BecauselandfillsneedtodealwithJapaneseknotweedinthisway,itisadvisabletocontactthelandfillsiteseveraldaysbeforeanyofthismaterialistakentheretoallowasuitableareatobepreparedforitsdisposal.
Ifyouneedinformationonthenearest
appropriatelandfilltoyoursite,callus
on08708506506.
Additionalinformation,including
detailsoflandfilltaxexemptionscan
beobtainedfromtheNetRegswebsite,
www.netregs.gov.uk/netregs/processes
28 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites29
6.2 Duty of care for hauliersBeforeacceptingwastematerialfortransferoffsiteyoumustinspectitforJapaneseknotweedcontaminationunlessyouknowitispresentalready.Youmustensurethatyoucomplyfullywithyourwastedutyofcareand,ifthematerialishazardous,therequirementsoftheHWR2005mustalsobemet(seepage6-7).Ifyoutakeittoalandfill,thatfacilitymustbelicensedorpermittedtoreceiveit.YoumustinformthelandfilloperatorthatthewastecontainsJapaneseknotweedsothathecandisposeofitappropriatelywithinthesite.
Asahaulier,youshouldnotacceptinfestedwasteunlessyoucanguaranteethatyoucandisposeofitappropriately.IfyouareawareofwasteproducerswhoarefailingtoinformtheirhauliersaboutJapaneseknotweed,oryouknowhaulierswhoareknowinglydisposingofJapaneseknotweedinfestedmaterialinappropriately,youshouldletusknowbycallingourincidenthotlineon0800807060.
Youmustalsomakesurethatwhenyouareremovingmaterialoff-site,yourvehiclesdonotcarrypiecesofJapaneseknotweedrhizomeonthemandthatvehiclesaresuitablycoveredorenclosedtopreventJapaneseknotweedescapingwhenitisbeingmoved(seeSection7).Youshouldbrushvehiclesdownvigorouslyorjet-washthemandtheninspectthemfortrappedpiecesofrhizome.
Somewastedisposalactivitiesthatweconsidersafetotheenvironmentdonotrequireawastelicence.Theseareclassedasexemptfromwastelicensing.TherearenowastelicensingexemptionsavailablefortheuseofJapaneseknotweed-infestedsoilsandwewilltreatanyuseofthismaterialasawasteoffence.Youcanonlyreuseknotweed-infestedsoilsaftertreatment.YoucanonlydisposeofJapaneseknotweed-infestedsoiloff-siteatasuitablylicensedorpermittedlandfill.Youcannotdisposeofitwithothersurplussoilandyoumustnotsellitastopsoil.
Anyonewhodoesnotdisposeoff-site
ofanymaterialcontainingJapanese
knotweedappropriatelymaybe
prosecutedunderSections33and34
oftheEPA1990andSection14ofthe
Wildlife&CountrysideAct1981.Ifyou
needadvice,calluson08708506506.
HowdoImovesoilcontainingJapaneseknotweed?YoushouldtrytomoveJapaneseknotweedinfestedsoilaslittleaspossible.You
needtothoroughlycleanvehiclesafteryouhaveusedthem.Avoidusingvehicles
thatarelikelytotrappiecesofrhizome,particularlythosewithcaterpillartracks.
Remember,justfinger-nailsizespiecesofrhizomecanleadtoitspreadingfurther.
7.1 Moving soil on-site TheJapaneseknotweedmanagementplan(AppendixVandVI)shouldreducetheneedtomovesoil.Youneedtoassessthehaulageroutesyouplantotakeforrisks,avoidingwatercourses,transportcorridorsandareasofhighconservationandamenityvalue.IfhaulageroutescrossareasfreefromJapaneseknotweed,soilshouldbeprotectedwithalayerofrootbarriermembrane.Thisshouldbeprotectedwithalayerofsandaboveandbelowtherootbarriermembrane,andasurfacelayerofhardcore.ThismaterialcanbeburiedwithintheJapaneseknotweedcell,asdescribedabove.
Youshouldclearlymarkoutyourhaulagerouteswithtape.YoushouldlimitaccesstotheseareastovehiclesinvolvedinmovingJapaneseknotweed.Youmustdecontaminatevehiclesbeforetheyleavethearea.
7.2 Moving soil off-site WhenyoutransportsoilinfestedwithJapaneseknotweedtolandfill,itisessentialtocarryoutstricthygienemeasures.Ifyoudonotfollowthesestandards,thismayleadtoJapaneseknotweedspreading.Japaneseknotweedisaparticularproblemalongtransportcorridors,whereitinterfereswiththelineofvisionandcancauseaccidents.
Werecommendthatyoushouldonlyfilltrucksuptoamaximumof20cmfromthetop.Youmustsealthevoidwithawell-securedmembrane.Youshoulduseenoughmembranetoletthesoilbesealedintoatemporarycellfortransporting.Itisveryimportantthatyoucontainthesoiltopreventanymaterialbeinglostwhenitismoved.Tocontainthesoilintheshort-term,youcanusealowerspecificationofmembrane(seeglossary).
7.3 Decontaminating vehicles YoushoulddecontaminatetheoutsideofvehicleswhenevertheyleaveanareacontaminatedwithJapaneseknotweed.YoushouldcleanvehiclesbeforeusingthemtomoveJapaneseknotweed.Youshouldcleantherearofthetruckafterithasfinishedmovingsoil.Youshoulduseapressurewasherandstiff-hairedbrushestocleanthevehicle,makingsurethatyouthoroughlyscouranyareasthatmightretainrhizome.Youneedtopayparticularattentiontotyretreadsandwheelarches.AnymaterialdislodgedduringthisprocessmustbeincludedwithintheJapaneseknotweedwaste.Youshouldonlycarryoutthisprocessoverarootbarriermembranelayerorhardsurfacethatcancontainandcollectthematerialwashedoff.Youmustnotletthismaterialcontaminatedrains,ditchesorwatercourses.
Peoplewhoknowwhatrhizomelooklike
shoulddothecleaning.Youshouldcarry
outathoroughinspectionbeforethe
vehicleisusedforotherduties.
30 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites31
8.4 What do I do if Japanese knotweed starts to grow through tarmac and other engineered surfaces and structures?OnceJapaneseknotweedbreaksthroughanengineeredsurface,therearelimitedwaysofmanagingit.Thereisarestrictedchoiceofherbicides,limitedtothoseproductsthathavebeenapprovedfortreatmentonhardsurfaces.Itisessentialthatyourefertothelabelconditionsaboutusingtheherbicidebeforetreatment.Someformulationsofglyphosateareapprovedfortreatinghardsurfaces,andthesewouldbesuitable.ItisadvisabletolettheJapaneseknotweedgrowbeforetreatingit,toallowthemaximumsurfaceareaofleaffortheherbicidetotransfertotherhizome.Youshouldseriouslyconsiderremovingthehardsurfaceandtreatingtheinfestation,beforerelayinganintactsurfaceafteryouhavedestroyedtheinfestation.
Preventionis,withoutdoubt,betterthancure.IfwedonotmanageJapaneseknotweedappropriatelyandallowittodamagenewstructures,therearelimitedwaysofcontrollingit.Herbicidesarelicensedforspecifickindsoftreatment,andmanychemicalsthatmayhavebeenusedbeforeahardsurfacewaslaidcannotbeusedfortreatingJapaneseknotweedthatisgrowingthroughtarmac.
8.5 How do I stop Japanese knotweed from neighbouring properties from re-infesting the site?
Co-ordinated control programmesIdeally,beforestartinganyJapaneseknotweedcontrolprogramme,youshouldconsideranyareasofJapaneseknotweedclosetotheboundaryofthesitewithintheprogrammeandnegotiatesomesortofarrangementwiththelandowner.Asitemanagermayconsiderincludingtheseareaswithinhistreatmentprogrammeasanactofgoodwill,iftheadditionalcostsarenegligible.Otheroptionsincludingallowingtheneighbouringlandownertopayformaterialcosts,suchasherbicide,orsharingthecostsaccordingtotheareaaffected.
Root barrier membrane methodsCarefullyusingagoodqualityrootbarriermembraneshouldbeaneffectivewayofstoppingJapaneseknotweedfromspreadingfromneighbouringinfestedsites.Wediscussthismethodinsection4above.
The law of nuisanceCommonlawrecognisesthecivilwrongsofnuisance,bothprivateandpublic.Aprivatenuisanceisdefinedasan“unlawfulinterferencewithaperson’senjoymentofland,orsomerightover,orinconnectionwithit”(ReadvLyons&CoLtd1945)andonlyapersonwithalegalrighttoexclusivepossessionmaysue.Apublicnuisanceoccurswherealargesectionofthepublicisaffected.Iftherewereacaseofpublicnuisance,itisimportantforyoutoestablishiftheaccusedpersoncouldhave‘foreseen’this.So,havingevidencethatyouhadlettheowneroftheneighbouringpropertyknowabouttheJapaneseknotweedwouldbeimportant.
8.6 How do I treat Japanese knotweed regrowth amongst valuable shrubs and planting schemes?Japaneseknotweedgrowthmayoccurinundisturbedareasofthesitewheretheoriginalvegetationistobepreserved.Regrowthmayoccurinnewlylandscapedareasasaresultofinadequatetreatmentprogrammesorcontaminatedtopsoilintroducedtothesite.Carefullyselectingherbicide,asdescribedinsection3,canavoiddamaginggrassedareas.Directapplicationtechniquesusingweed-wipers,orthestem-injectiontechniquecanavoidnon-targetdamage.
Thesteminjectiontechniqueinvolves
cuttingthecanenearitsbase,just
aboveanode.Thisleavesahollowtube,
downwhichadoseofherbicidecanbe
applied.Thismethodologyisdescribed
atwww.projects.ex.ac.uk/knotweed/
standardmethodology.pdf
HowwillJapaneseknotweedaffectusingthesiteinthelongterm?
8.1 Managing buried Japanese knotweed in thelong termIfJapaneseknotweedmaterialhasbeenburiedasdescribedabove,subsequentregrowthishighlyunlikely.Thelikelihoodofthematerialgrowinginthelongtermwilldependonhowitwastreatedbeforeitwasburied.Iftheinfestationwaseffectivelytreatedwithherbicideandtherhizomestressedbybeingbrokenupand/ordryingout,thiswillgreatlyreducethechanceofitsurvivinginthelongterm.Japaneseknotweedrhizomehasbeenknowntosurviveforatleast20years,soitisimportanttoconsidermanagingitoveralongperiodoftime.Siteownersinthefuturemustbeabletoseearecordthatgivesdetailsofthepreciselocationandnatureoftheburial.Itisimportantthatthesiteisnotdisturbed.Ifithastobedisturbed,thecontaminatedmaterialmustbemanagedaccordingtothiscodeofpractice.
8.2 Controlling potential regrowth around the siteWhendevelopingaJapaneseknotweedmanagementplan,youneedtoconsiderthepotentialforregrowtharoundthesite.Whenyouconsiderthat0.7gramofrhizomeisenoughforittoregenerate,youmayexpectsomeregrowthandyouwillneedtobuildthatintoanyagreementbetweenclientandcontractor.Regrowthtendstohappenwhennotenoughmaterialhasbeenexcavatedfromtheinitialinfestation,trackedvehiclesorpoorhaulagehasspreadsmallfragmentsandwheninadequatelytreatedmaterialhasbeenreusedforlandscapingpurposes.Regrowthfromfragmentedrhizomerespondswelltoherbicidetreatment,orcarefuldigging.Ifregrowthoccursduetoundisturbedrhizomethatwasoverlookedduringthesurvey,youwillneedalong-termcontrolprogramme.
8.3 Advice to new ownersItisgoodpracticetoadvisethenewownersofthepropertythatthesitewassubjecttoaJapaneseknotweedmanagementplan.Youshouldincludethiswithinavendorstatementofdeclaration.Itispossibleforisolatedregrowthstooccurinthefuture,andgoodadvicewillhelptopreventthesefrombecomingestablished.Japaneseknotweedfromneighbouringlandmayalsore-invadethesite.TheCornwallKnotweedForumwebsitewww.cornwallknotweed.org.ukgivesadvicetohouseholdersonmanagingJapaneseknotweed.
32 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites33
Appropriate method of herbicide application can avoid non-target damage.
Activeingredient:Thechemicalcomponentofaherbicidethatactuallykillsordebilitatestheplant.
Axil:Theanglebetweentheleafstalkofaplantandthestem.
BASIS:Aqualificationoftechnicalcompetenceforpeoplewhouse,store,selloradviseontheuseofpesticides.BASISisanorganisationcommittedtomakingsurepeopleinvolvedinhandlingandusingpesticidesarecompetent.BASISmaintainaregisteroftrainedadvisors,whoneedtodemonstrateanannualprogrammeofcontinualprofessionaldevelopmenttomaintaintheirqualification.DetailsontheBASISProfessionalRegisterareavailablefrom34,StJohnStreet,Ashbourne,DerbyshireDE61GH.Tel:01335343945.
Brownfield:Asitethathasbeenpreviouslyusedinamannerthatrequiresremediationbeforeitisusedagain.Suchsitesareoftenpost-industrialsitesorderelictbuildingsandoftenhavecontaminatedlandandotherwasteissuesassociatedwiththem.
Bund:Shallowpileofsoil,spreadouttoachieveadepthnogreaterthan1m,preferably0.5m.Bundscaneitherbeonthesurface,oroccupyvoidstocreatealevelsurface.BundsshouldhavethebulkoftheJapaneseknotweedrhizomeconcentratedonthesurface,tofacilitateregrowthsuitableforherbicidetreatment.
Canes:Tall,hollow,bamboo-likestems.
Clerkofworks:PersonresponsibleformanagingalltheJapaneseknotweedonsite.TheclerkofworksoverseestheJapaneseknotweedmanagementplanandensuresallstaffonsiteareawareoftheirrolewithregardsJapaneseknotweedmanagement.
ControlofPesticidesRegulations(CoPR)1986:CoPR1986requireanypersonwhousesapesticidetotakeallreasonableprecautionstoprotectthehealthofhumanbeings,creaturesandplants,safeguardtheenvironmentandinparticularavoidthepollutionofwater.ForapplicationofpesticidesinornearwaterapprovalfromtheEnvironmentAgencyshouldbesoughtbeforeuse.
Crown:Thevisiblepartoftherhizomefromwhichcanesgrow.Crownscanproducemanynewcanesand,becauseoftheirsize,canberesistanttoburningordryingout.
Dormant:Thestateinwhichanorganismisstillalive,butdisplayslittleevidenceoflife.
Dutyofcare:Section34oftheEnvironmentalProtectionAct1990(EPA90)imposesadutyofcareonpersonsconcernedwithcontrolledwaste.Thedutyappliestoanypersonwhoproduces,imports,carries,keeps,treatsordisposesofcontrolledwaste,orasabrokerhascontrolofsuchwastes.Breachingthedutyofcareisanoffence,withapenaltyofanunlimitedfineifconvictedonindictment.
EnvironmentalProtectionAct1990(EPA1990):EPA1990containsanumberoflegalprovisionsconcerning“controlledwaste”,whicharesetoutinPartII.AnyJapaneseknotweedcontaminatedsoilorplantmaterialthatyoudiscard,intendtodiscardorarerequiredtodiscardislikelytobeclassifiedascontrolledwaste.Themostrelevantprovisionsareinsections33and34.
Fly-tipping:Illegaldisposalofwasteintotheenvironment.
Sourcesofadditionalinformation9.1 Additional informationYoucanfindgoodpracticeonmanagingJapaneseknotweedontheinternet.TheCornwallKnotweedForum(www.cornwallknotweed.org.uk/environment/knotweed)providesusefulsupportinginformation.Thisdocumentupdatestheadvicewithinthatwebsitefordevelopersandhauliers.DevonKnotweedForumadvicecanbeobtainedfrom:www.devon.gov.uk/index/environment/natural_environment/biodiversity/japanese_knotweed/advice_land_and_gardener.htm
Electronicversionsofthiscodeareavailableon:www.environment-agency.gov.uk/subjects/conservation
AdditionalinformationonJapaneseknotweedmanagement,includinginformationonlandfilltaxcreditscanbeobtainedon:www.netregs.gov.uk/netregs/processes
TherearevariouscontrolmethodsavailablefromcompaniesspecialisinginJapaneseknotweedmanagementondevelopmentsites.YoushouldbecarefulofproductsandmethodsthatclaimtoquicklyeradicateJapaneseknotweed.
9.2 Some useful resources:Child,L.E.andWade,P.M.(2000)TheJapaneseKnotweedManual.PackardPublishingLimited,Chichester.ISBN1853411272
CornwallKnotweedForum(2001)Japaneseknotweed.Guidanceforhouseholdersandlandowners.
WelshDevelopmentAgency(1998)ThecontrolofJapaneseknotweedinconstructionandlandscapecontracts:Modelspecification.(FormerWelshDevelopmentAgency),WelshAssemblyGovernment,Cardiff.
WelshDevelopmentAgency(1998)TheeradicationofJapaneseknotweed:Modeltenderdocument.(FormerWelshDevelopmentAgency),WelshAssemblyGovernment,Cardiff.
Glossary
34 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites35
Formulation:Aparticularherbicidetradedunderaspecificname.Differentformulationsofherbicidemaysharethesameactiveingredient,butaredesignedforuseindifferentsituations.Forinstance,onlycertainformulationsofglyphosateareapprovedforuseinornearwater.
Greenbelt:Areaofundevelopedlandinproximitytoacommunitythathasbeenpreservedtoconservetheaestheticbeautyofthelocation.Theseareasarereferredtoas‘greenwedges’inWales.
HazardousWasteRegulations2005(HWR2005):HWR2005containprovisionsaboutthehandlingandmovementofhazardouswaste.Consignmentnotesmustbecompletedwhenanyhazardouswasteistransferred,whichincludedetailsaboutthehazardouspropertiesandanyspecialhandlingrequirements.Ifaconsignmentnoteiscompleted,awastetransfernoteisnotnecessary.Materialcontainingknotweedthathasbeentreatedwithherbicide,maybeclassifiedashazardouswaste.
Hazardouswaste:HazardousWaste–wastewhichbyvirtueofitscomposition,carriestheriskofdeath,injuryorimpairmentofhealth,tohumansoranimals,thepollutionofwaters,orcouldhaveanunacceptableenvironmentalimpactifimproperlyhandled,treatedordisposedof,ascontrolledintheECDirectivesonHazardousWasteanddefinedbySpecialWasteRegulations1996(asamended)(schedule2).
Heave:Physicaldisruptionofahardsurfacecausedbyanupwardstress.
Hybrid:Aplantoranimalthatresultsfromreproductionbytwodifferentspecies.
Membrane:Inthiscode,membranedescribesarelativelylowspecificationprotectivelayerusedforcontainingJapaneseknotweedwhenitisbeingtransported(sections5.1,6.1,6.2,7.2).Comparewith‘rootbarriermembrane’,below.
Perennial:Aplantthatcontinuesitsgrowthfromyeartoyear.
Persistentherbicide:Aherbicidethatcontainsanactiveingredientthatwillnotbeswiftlydegradedafterithasbeenapplied.Thiscansometimeslimitthemannerinwhichtreatedsoilcanbereusedordisposedof.
Rhizome:Undergroundstem.EnablesJapaneseknotweedtosurviveover-winter,whenthecanesdieback.Smallsectionsofrhizome,aslittleas0.7gcanregrowintoanewplant.Rhizomatous:Oforpertainingtoarhizome.
Rootbarriermembrane:Highspecificationmembraneusedforhighlystressedshort-termprotection,suchashaulageroutes(section2.2,7.1and7.3),orcontainingJapaneseknotweedinthelongterm(sections4,5and8.5).Rootbarriermembranesmustbemadeofamaterialthatisfitforpurpose.Itshouldbemadeofamaterialthatcanbe:
a) usedwithoutdamage;
b) providedinlargesizes,tominimisetheneed forseals;
c) sealedsecurely;
d) remainintactforatleast50years(guaranteed bythemanufacturer);
e) resistUVdamageifusedwhereitisexposed tosunlight;
f) buriedwithoutpollutinggroundwater fromchemicalsleachedfromit.Comparewith ‘membrane’,above.
Sett:Thesystemoftunnelsandchambersusedbybadgersandprotectedbylaw.
Tines:Longpointedteethattachedtoadiggerbuckettorakeoutrhizome.
Viable:Capableofgrowingintoanewplant.
Wasteexemption:Whenthedisposalofwasteisdeemednottopresentarisktopublichealthortheenvironment.
WasteManagementLicensingRegulations(WMLR)1994:WMLR1994describe‘wasterelevantobjectives’inParagraph4ofSchedule4.Theseobjectivesrequirethatwasteisrecoveredordisposedof“withoutendangeringhumanhealthandwithoutusingprocessesormethodswhichcouldharmtheenvironmentandinparticularwithoutrisktowater,air,soil,plantsoranimals;orcausingnuisancethroughnoiseorodours;oradverselyaffectingthecountrysideorplacesofspecialinterest”
Wasterelevantobjectives:SeeWasteManagementLicensingRegulations(WMLR)1994,above.
WildlifeandCountrysideAct1981(WCA1981):Section14(2)statesthat“ifanypersonplantsorotherwisecausestogrowinthewildanyplantwhichisincludedinPartIIofSchedule9,heshallbeguiltyofanoffence.”JapaneseknotweedisoneoftheplantslistedintheSchedule.
36 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites37
AguidetoJapaneseknotweedrhizomeidentificationandexcavation
AguidetoJapaneseknotweedrhizomeidentificationandexcavation
“Finger-nailsizedsectionsofrhizome
0.7ginweightcanregenerateintoanew
knotweedplant.”
i) What is Japanese knotweed?JapaneseknotweedFallopia japonicawasintroducedintotheUKduringthemid-nineteenthcenturyasanornamentalplant.IthassincebecomeoneofthemostproblematicinvasiveweedsinEurope(seeSection1ofCode)
Japaneseknotweedisaperennialweed,producingtallcanes,upto3m(10feet)inheightduringthesummer.Thecaneshavecharacteristicpurpleflecks,andproducebranchesfromnodesalongitslength.Thesebranchessupportshovel-shapedleavesandclustersofwhiteflowersinautumn.Thecanesdieoffinwinter,turningbrownandsheddingtheirleaves.Thisproducesdensemulchthatprecludesthegrowthofnativeplants.
ii) What is Japanese knotweed rhizome?Japaneseknotweedcanesgrowfromdensecrownsthatalsoproduceextensiveundergroundstems,calledrhizomes.Theserhizomesalsoproducefine,white,hair-likeroots.Itishardtostatewithcertaintythelikelyextentofrhizomespreadfromtheparentplant.Researchhasshownthatrhizomecangrowadistanceofatleast7m(23feet)andachieveadepthofatleast2m(6feet)fromtheparentcrown.However,theactualextentoftherhizomecanvaryconsiderablydependingonthesoiltypeandthehistoryofthesite.Manyknotweedinfestationsstartlifeasaresultoffly-tippedwaste,andrepeatedapplicationsofwasteontopoftheinitialinfestationcanresultinadeepmatrixofrhizome.
38 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites39
Thisguideshouldbeusedinconjunctionwiththe
EnvironmentAgencycodeofpractice,‘managingJapanese
knotweedondevelopmentsites’.Ithasbeenproducedas
aseparateguidetofacilitateuseduringexcavations.
AppendixI
Inadditiontotherhizomedescribedwithintheidentificationchart,verynewrhizomegrowth,delicateandwhiteinappearance,canbefoundduringthegrowingseason.
v) How do I remove rhizome?Putsimply,removetherhizomewithextremecare.Itisimportanttoreadthecodeofpracticebeforestartingexcavation.Themajorityofknotweedrhizomeisconfinedtothetop0.5mofsoil.Removethesoilbyfirstscrapingoffthecrownsandsurfacerhizomeandputtingtooneside.Crownsandrhizomecanbedriedandburned(seeSection5.2ofCode)priortotreatmentwiththeremainingsoil.Crownmaterialinparticularisresistanttoburning;thereforeitisimportanttoregardthismaterialasstillpotentiallyinfectious.
Thenext0.5-1mofsoilcanthenberemovedandputaside,andthentheremainingsoiltoadepthofapproximately3mcanbeexcavated.Thismaterialshouldformthebaseofabund(SeeSection5.5ofCode),orthetoplayerofburiedmaterial(SeeSections5.4and4.1ofCode).Thisprocessofexcavationcanbeproportionedtoanydepthofexcavation,ratherthanadoptingthe3mgeneraliseddepth.
Guidanceonthecontainmentandmovementofknotweed-infestedsoilisprovidedwithinSections2,6and7oftheCodeofPractice.
Carefuluseoftheinformationwithinthisguideshouldenableoperatorstoeffectivelyinspecttheedgeoftheirexcavationforremainingrhizome.Dependingonthehistoryofthesite,thedepthtowhichknotweedrhizomeextendscanvarybetween0.5m–10m.Thehistoryoftheinfestation,soiltypeandthewatertablecanallhaveaprofoundimpactontheextentofrhizome.Situationsinwhichrhizomeisgreaterthan3mtendstobeassociatedwithsituationsinwhichadditionalwastehasbeenregularlydumpedonanestablishedknotweedstand,orwind-blownsandhascreatedadunesystem.
Carefulexcavationofrhizomehasthepotentialtosignificantlyreducethevolumeofwasteremovedinsteadofsimplyexcavatinga7mx3mvolumeofsoil.Italsoensureseffectiveremovalinsituationswherea7mx3mexcavationisanunder-estimate.Inallcasestheprecautionaryapproachmustbeadoptedratherthanriskleavingrhizomebehind.
iii) Why is it important to be able to identify Japanese knotweed rhizome?Whilstknotweedcanregeneratefromsmallsectionsofcane,mostknotweedintheUKarisesfromrhizomeandcrownmaterial.Finger-nailsizedsectionsofrhizome0.7ginweightcanregenerateintoanewknotweedplant.Itappearsthattheregenerativepotentialofrhizomevaries.Thick,oldwoodytissueappearstobelessabletoproducenewgrowththancrownmaterialorthinnersucculentrhizome.Thishasimplicationsforthoseexcavatingknotweedrhizomes,wherethereisariskofthinterminalrhizomefromtheedgeofthecutbeingoverlooked,whichwouldhaveahighregenerativepotential.
Thereareoftensituationsinwhichitisnecessarytobeabletoidentifyrhizomewithoutthebenefitofintactknotweedcanesforassistance.Ifasiteisundisturbeditisfairlyeasytorecognisecharacteristicsummergrowth,orthedeadwintercanes.Ifthesitehasalreadybeenscraped,itisnecessarytoinspectthewastematerialforevidenceofknotweed;deadcanes,leavesandrhizome,toestablishiftheweedispresentonsite.Knowledgeofrhizomeidentificationisthenrequiredtoidentifythelocationandextentoftheinfestation.
Thecostofknotweedmanagementcanbesignificantlyreducedifknotweedandnon-knotweedwastestreamscanbekeptseparate.Ifpoorinitialmanagementofasitehasalreadyprecludedthisoption,thisshouldbeofgreatconcerntoanysubsequentdeveloper.
Wastehauliersalsoneedtotakecaretoinspectwastematerialpriortoacceptingit(SeeSection6.2ofCode).SoilcontainingviableknotweedmaterialisnotsuitablefordisposalunderanexemptionfromSection34oftheEnvironmentalProtectionAct1990.Section34imposesadutyofcareonapersonwhoproduces,imports,carries,keeps,treatsordisposesofcontrolledwaste,oractsasabrokerforsuchwastes.
iv) How do I recognise rhizome?Anidentificationchartforknotweedrhizome,andacomparisonwithothercommonlyencounteredroots,isprovidedwithinAppendixII.TheformerWelshDevelopmentAgency,nowpartoftheWelshAssemblyGovernment,hasproducedatabularguidetotheidentificationofknotweedrhizomethatisreproducedinAppendixIIIwiththeirkindpermission.
40 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites41
Plants commonly found on development sites
External appearance of root or rhizome
Snap Test
Scrape Test
Notallrhizomeregeneratesinthesamemannerandthefactorsthatdeterminerhizomeregenerationarethesubjectofresearch.Itappearsthatolderrhizomebecomeswoody,andtendstobeutilisedbytheplantforfoodstorage,whereasthefreshyoungrhizomeismorecarrot-likeandmuchmoreinfectious.Therefore,thesmallpiecesattheextremeedgeoftherhizomeringarepotentiallythemostinfectious,andthereforerequirethegreatestofcare.Itisgoodpracticetoexcavateanother0.5maroundtheperimeterofthecutafterallrhizomehasbeenapparentlyremovedasafurtherprecaution.
Rhizomeisanundergroundstem,ratherthanaroot,andwilltendtospreadlaterally.Therhizomeattheperipheryofthematrixwilltendtobeshallow,thereforetheexcavationusuallydescribesasaucer-shapedprofile.
Havingexcavatedtherhizomeitisessentialthatwastestreamsarekeptseparateandthatrhizomeisnotallowedtocontaminatespoilthathasbeenremovedfromareasfreefromrhizome.
Remember:Donotexcavaterhizomeunlessyou
haveto,especiallyifyoudonothavethe
capacitytotreatthematerialonsite.
A0.7gpieceofrhizomeisapproximatelythesizeofyourlittlefingernail,andthismaybecapableofgrowingintoanewplant.
Thematrixoftherhizomewillvaryinsizeandextent,dependingonthenatureandhistoryofthesite.Carefuluseofthisguidewillminimisethewaste
youproduceandsignificantlyreduceyourcosts.
Rhizomemayremaindormantforatleast20years.Dormantrhizomemayregrowifitisdisturbed.Lackofregrowthisnotevidenceoferadication.
Avoidspreadingrhizomebyfollowingtheguidancegivenwithintheknotweedcodeofpractice.
IfyouspreadrhizomeintotheenvironmentyoumaybeliabletoprosecutionundertheWildlife&CountrysideAct1981.
Root / rhizome identification chart - Japanese knotweed
Japanese knotweed Fallopia japonica(and other Asiatic invasive knotweeds).Japaneseknotweediscommonlyencounteredonbrownfieldsites,wheresoildisturbanceandfly-tippingarecommon.Closeproximitytorivers,roadsandrailwaysmayalsoprovideasourceofinvasion.
42 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites43
Colour:Darkbrown,lighterwhendried.
Texture:Smoothskin,becomingroughwhendesiccated.
Features:oftenforminglongknottylengths.Maysupportsmallredbuds,particularlyoncrowns(baseofstem).Finehair-likerootscommon,particularlyonthinnersections.
Snapability:Easy.Verycarrot-likeinstructureandcolourwhenfresh.Morewoodywhendry.Oldermaterial,particularlynearthecrown,canbeverywoody.Colourcanvaryfromdeepredtopaleyellow,withorangethemostcommon.Youngerfreshmaterialusuallyhasadifferentcolouredcore.
Outer layer:Thinskin,easilyremovedwhenfresh.
Inner layer:Palethreadsoftenrunthroughdarkerfibrousflesh,particularlyinlargerrhizome.Oftenvariationsincolourthroughrhizomewhensplitlengthways.Crownmaterialisoftencakedwithsoilandcanbehardtorecognise.Cleaningshouldrevealredbudsandcharacteristicflesh.
AppendixII
Plants commonly found on development sites
External appearance of root or rhizome
Snap Test
Scrape Test
Root / rhizome identification chart - knotweed
Buddleja (Butterfly bush):Introducedshrub(intro:1890),colonisingwastegroundandmasonry.Spreadbyseed.Pink,purpleorwhiteflowers.Corkybark.Silverundersidetoleaves.
Colour:Palebrown.
Texture:Bark-like.
Features:Barkeasilydamagedandrevealingthewoodycore.Tough.
Snapability:Verypoor.Tendstoripratherthanbreakcleanly.Distinctcore.
Outer layer:Thinwrinkledbark.
Inner layer:Whitewood.
Root / Rhizome identification chart - other common plants
Plants commonly found on development sites
External appearance of root or rhizome
Snap Test
Scrape Test
Dock:Commonondisturbedgroundandintopsoil.AgriculturalweedandcoveredbytheWeedsAct1959.Closestnativeplanttoknotweed,sosimilarrootappearance.
Colour:palered/brown.
Texture:Fleshyskin.
Features:Tapering,withbranchesclusterednearthetip.Lackingtheknottyappearanceofknotweed.
Snapability:Easy.Rubbery,butlacksthecarrot-likesnappinessofknotweed.Coreissimilarcolourtotherestoftheroot,lackingthecolourvariationofknotweedrhizome.
Outer layer:Thinskin,similartoknotweed.
Inner layer:fleshy,withadistinctcore.Orange/yellowincolour,butusuallypalerthanknotweed.
44 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites45
AppendixIII
Plants commonly found on development sites
External appearance of root or rhizome
Snap Test
Scrape Test
Root / rhizome identification chart - knotweed
Sycamore (and most other trees):Treesarecommoncolonisersofwasteground.Theirrootsareoccasionallymistakenforrhizome.
Colour:Mid-brown.
Texture:Fairlysmoothandeven.
Features:Doesnotfragmentaseasilyasknotweed.Tendtoremainintaperedsections.Finerootlets.
Snapability:Verypoor.Verywoody,tendingtobreakandtearratherthansnap.Fairlyuniformincolourandstructure.
Outer layer:Toughbark.
Inner layer:Palecolouredwood.
Root / Rhizome identification chart - other common plants
Plants commonly found on development sites
External appearance of root or rhizome
Snap Test
Scrape Test
Elder: Nativeshrub,typicalofdisturbedgroundandwasteland.Whiteclustersofflowersinspring,blackberriesinautumn.
Colour:Palebrown/yellow
Texture:Fleshyandsmooth.Wrinkledifdesiccated.
Features:Fleshyrootlets.
Snapability:Reasonable.Thinsectionssnap,butlargersectionsaretoowoody.Tendstotear.
Outer layer:Skineasilyremoved.
Inner layer:Whitefleshylayerwithapalewoodycore.
46 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites47
General characteristics Yes No
Twig-likeappearance
Table for the identification of Japanese knotweed rhizome
Fleshywithhardnesslikecarrot
Exterior of rhizome Yes No
Colourdarkbrown,likecoffeegranules
Textureoftheouterbarkleathery
Brittlewhenfresh,breakeasilylikecarrot
Youngrhizomeiswhiteandverysoft
Whenbarkisremoved,tissueispaleorange/yellow
Nodesat1-2cmspacing
Nodesslightlyenlargedand‘knotty’
Atnodeswhitefibrousrootsarecommon
Ifpresent,freshbudsatnodesarered/pink
Interiorofrhizome
Longitudinal view Yes No
Colour:paleorangeandlightyellow,similartoacarrot
Centralcoreisusuallydarkorange/brown,likerust,andsometimeshollow
Cross section Yes No
Cortexwithrayscomingfromcentre,likespokesfromawheel
TOTAL
Ifthe‘yesscoreisgreaterthanthe‘no’
score,thentreattheidentifiedrhizome
asJapaneseknotweed.
ReproducedwithkindpermissionoftheformerWelshDevelopmentAgency,nowpartoftheWelshAssemblyGovernment.
ManagementplanforJapaneseknotweedat:
Tableofcontents
1. INTRODUCTIONTOTHESITE 2 1.1 Descriptionofthesite
1.2 Sitemanagementobjectives
1.3 Limitationsandthreatstomanagementobjectives
1.4 Inventoryofthesite
2. OVERVIEWOFMANAGEMENTPLAN 3 2.1 Briefdescriptionofmanagementplan
2.2 Settingpriorities
2.3 Preventingfurtherspread
3. SPECIFICCONTROLPLANSFORJAPANESEKNOTWEED 4 3.1 Managementobjectives
3.2 Managementoptions
3.3 Actionsplanned
3.4 Howactionswillbeevaluated
3.5 Resourceneeds
3.6 Resultsofevaluation
4. SUMMARYINFORMATION 5 Table1: Priorityareas
Table2: Controlmethods
Table3: Implementationschedule
Table4: Projectedresourcesandcosts
5. REFERENCES 6
6. APPENDICES 7 Appendix1. SitemapsandJapaneseknotweeddistributiondaps
Appendix2. Japaneseknotweedrecordingsheet
Appendix3. Formsforcollectingmonitoringdata
Appendix4. Herbiciderecords
Appendix5. Wasterecords
Appendix6. Usefulcontacts
Periodcovered:
Prepairedby: Date:
48 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites49
AppendixIV AppendixV
Descriptionofmethodstobeemployedtopreventfurtherspread:Includeforexample: • IsolationofJapaneseknotweedonsitebyfencingtoavoiddisturbanceduringtreatment.
• Assessmentofriskofre-invasionofJapaneseknotweedfromadjacentland.
• LiaisonwithadjacentlandownerstotreatJapaneseknotweedwhichposesarisktothesite.
• ProcedurestoensurethatimportedmaterialsarefreefromJapaneseknotweed.
• Identificationofdesignatedhaulroutesthroughsitetoavoidcontamination.
Descriptionoftrainingtobegiventositeoperatorsandcontractorsduringdevelopment:Includeforexampleidentificationoftheplant(bothaboveandbelowgroundparts)andtrainingonsitepracticesto
preventfurtherspread.
2.3 Preventing Further Spread
Examples: • AreasofJapaneseknotweedonsitewhichrequirerapidtreatmentwillbeidentified.
• Preventionoffurtherinfestationoftheplantonthesiteisapriority.
• Replacementvegetation/habitatwillbeconsideredratherthanjusteliminatingJapaneseknotweed.
• Controlmethodswhichsuitthelocationandtimescalewillbeadopted.
• Implementationwillbebasedontheaboveinformation.
• Regularmonitoringwillbecarriedout.
• Managementwillberevisedinresponsetofeedbackfromtheabove.
Assignprioritytoeachmanagementobjective:(e.g.High,MediumLow)-Recordprioritiesforeachlocationofthe
plantinTable1.
2.2 Setting Priorities
AllocatepersonneltooverseeJapaneseknotweedmanagementandtoberesponsibleforsign–offattheendofthetreatmentperiod:
Descriptionofthesiteboundaries,topography,access,specialfeatures:Includemapsofsitepreandpost
developmentinAppendix1.
DescriptionoftheJapaneseknotweeddistributiononsiteandadjacenttothesite:IncludedetailedmapsshowinglocationofJapaneseknotweedandexactareacovered(allocateauniqueidentification
numbertoeachlocationofJapaneseknotweedonsitee.g.JK001,JK002etc).
Completearecordingsheetforeachlocation(seeAppendix2)IfJapaneseknotweedispresentonadjacentland,record
distributionanddetailsoflanduseandlandownership.
1.4 Inventory of the Site
DescriptionofhowthepresenceofJapaneseknotweedposesathreatto,orlimitsmanagementobjectives.Includeforexample: • Increasingcostsofdevelopment
• Delaysinschedulingofworks
• Damageorpotentialdamagecausedbytheplant
• PotentialforspreadofJapaneseknotweedfromwithinandoutsidethesiteboundary
(e.g.withinthesite,fromadjacentlandorviawatercourses)
• PotentialforimportofJapaneseknotweedonmaterials
1.3 Limitations and Threats to Site Management Objectives
Briefdescriptionoftheexistingsite(priortoanydevelopment):Includepresenceofanynatureconservation
features–e.g.protectedspecies;vegetationtoberetained;watercourses(includeproximityofstreamsorriversif
adjacenttothesite);buildingstoberetained;drainageonsite;otherrelevantfeatures.
Briefdescriptionoftheproposeddevelopment:Includeanyproposedimportorexportofsoils.
Briefdescriptionofthesitepost-development:Includeanypartsofthesitedesignatedforlandscaping,
conservationareasetc.
1.1 Description of the Site
Briefdescriptionofsitemanagementobjectives:Includeproposedtimescaleandplansforrestoration/re-
planting.
1.2 Site Management Objectives
Overview of weed management planIntroduction to the site
2.1 Brief Description of Management Plan
DRAFT TEMPLATE DRAFT TEMPLATE
50 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites51
Sitename:
Responsiblemanager: Dateplanlastupdated:
Brieflydescribethelocationstobetreated,materialsandmethodstobeused,andanapproximatescheduleforcontrolandmonitoringactivities.RecorddetailsinTable2.
3.3 Actions planned (treatments and monitoring)
Viablecontroloptionsare: • Notreatment;
• Treatmentalternative1
• Treatmentalternative2etc.
Brieflydiscussthealternatives,indicatewhicharepreferredandtheconditions(sizeofareatreated,location,timing,
totalanticipatedcost,etc.)underwhichtheymaybeused.
Buildinrestrictedflexibilitytoallowconditionsonsitetobetakenintoconsideration.Statewhothesiteoperatives
shouldcontactwhennoneofthelistedalternativescanbecarriedout.
3.2 Management options
Establishmeasurableobjectivesfortheplannedcontrolactivities.Include: • theimpactondensity,cover,etc.thatyouwanttoachieve;
• thesizeoftheareainwhichyouhopetoachievethis;
• theperiodinwhichyouhopetoachieveit.
Examples: Objective1. EliminationofJapaneseknotweedonallpartsofthesitewithin5years.
Objective2. Reducepercentagecoverby50%on1haofthesitewithin2years.
Objective3. PreventionoffurtherspreadofJapaneseknotweedonsite.
Objective4. Co-ordinationwithadjacentlandownerstocommenceactivetreatmentofJapaneseknotweedin
adjacentareaswithin1year.
3.1 Management objectives (measurable)
Summary informationSpecific control plans for Japanese knotweed
Table 1 - Priority areas
Outlinethemethodsthatwillbeusedtomonitorcontrolactivitiesandthecriteriathatwillbeusedtoevaluatesuccessorfailureoftheprogram.Thecriteriaforsuccessshouldbebasedontheprogram’sobjectivesand
goals.(DatasheetstobeusedwhencollectingmonitoringdatashouldbeincludedinAppendix3).
3.4 How actions will be evaluated (criteria for success)
Estimatetheamountoftimeforstaff,materials,contractorsetc.andmoneythatwillberequiredtocarryouttheplannedcontrol,monitoringandevaluation.RecordinTable4.
3.5 Resource needs
Thissectionistobefilledinlater,preferablywithin1year,whenmonitoringdatahasbeentakenandevaluated.Theevaluationshouldbeusedtodeterminewhetheranyofthesections3.1-3.5aboveshouldbemodified.
3.6 Results of evaluation
Area Descriptionandjustificationsofpriority Prioritylevel
Table 2 - Control Methods
Area ControlMethod Carriedoutby
Table 3 - Implementation ScheduleScheduletheplanning,surveying,andtreatmentforJapaneseknotweedforatleastthenextyear.
TreatmentSchedule Date
Table 4 - Projected resources and costsRevisethistableannuallyaftercomparingestimatedtoactualcosts.
Item Description Projectedresources Projectedcosts ActualCosts
References
Listreferencescitedorused.Forexample:
Child,L.E.andWade,P.M.(2000)TheJapaneseKnotweedManual.PackardPublishingLimited,Chichester.ISBN1853411272
EnvironmentAgencyandCornwallCountyCouncil(1998)Japaneseknotweed.Howtocontrolitandpreventitsspread.EnvironmentAgency,Bodmin.
EnvironmentAgencyandCornwallCountyCouncil(2001)Japaneseknotweed.Guidanceforhouseholdersandlandowners.CornwallCountyCouncil.
WelshDevelopmentAgency(1998)ThecontrolofJapaneseknotweedinconstructionandlandscapecontracts:Modelspecification.FormerWelshDevelopmentAgency,nowpartoftheWelshAssemblyGovernment.
WelshDevelopmentAgency(1998)TheeradicationofJapaneseknotweed:Modeltenderdocument.FormerWelshDevelopmentAgency,nowpartoftheWelshAssemblyGovernment.
DRAFT TEMPLATE DRAFT TEMPLATE
DRAFT TEMPLATE
52 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites53
Remarks:
Attachcopiesofthemap(s)ofthesite,andofmapsdepictingtheextentoftheJapaneseknotweedonthesite.
Appendix 1 - Distribution maps
Appendices
ExampleofJapaneseknotweedRecordingSheet(completeanewsheetforeachareaofJapaneseknotweed).
Appendix 2 - Japanese knotweed recording sheet
Averageheightofstems
Max.stemdiameterat30cmaboveground
Vegetationcomposition
Proximitytowatercourses
Slope
>2.5m
>2.5cm
1-2.5m
1-2cm
<1m
<1cm
Mixtureofknotweed&othervegetation
Japaneseknotweedonly
SteepModerateFlat
Sitename:
Recordedby: Date:
Gridref: Siteref:
m m
AreaofJapaneseknotweed-NB.MarkoutlineofareaofJapaneseknotweedonsitemapandannotatewithsiteref.
no.Ifpatchmeasures<1.0m2,markas+onmapandannotatewithsiteref.no.
Yes No
Canal
Roundabout
Graveyard
Landscapedarea
Business/IndustrialHousing
Garden
Farmland
CarPark
Riverbank
Pond Seafront
Streamside
Roadverge
Woodland
Park
Shops
Other,specifyhedgerow
Dock
Railwayembankment
Wasteground
Recreationground
Publicbuildings
Landuse-Recordprimarylanduseas1andsecondaryuseas2etc.e.g.landscapedareaadjacenttoriverbankrecord
asRiverbank1;Landscapedarea2.
DRAFT TEMPLATE
Attachcopiesofdatacollectionsheets.
Appendix 3 - Forms used in collecting monitoring data
Attachdetailsofherbicidesused,doserateandapplicationratesanddatesapplied.
Appendix 4 - Herbicide records
AttachdetailsofwasterecordsforanymaterialcontainingJapaneseknotweedtakenoffsite.
Appendix 5 - Waste records
AttachdetailsofContractors,LocalAuthoritycontact,EnvironmentAgencycontact,adjacentlandownersetc.
Appendix 6 - Useful contacts
54 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites55
ManagementplanforJapaneseknotweedat:
Periodcovered:
Prepairedby: Date:N.E. Body
2006-2010
April 2006
56 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites57
Tableofcontents
1. INTRODUCTIONTOTHESITE 2 1.1 Descriptionofthesite
1.2 Sitemanagementobjectives
1.3 Limitationsandthreatstomanagementobjectives
1.4 Inventoryofthesite
2. OVERVIEWOFMANAGEMENTPLAN 3 2.1 Briefdescriptionofmanagementplan
2.2 Settingpriorities
2.3 Preventingfurtherspread
3. SPECIFICCONTROLPLANSFORJAPANESEKNOTWEED 4 3.1 Managementobjectives
3.2 Managementoptions
3.3 Actionsplanned
3.4 Howactionswillbeevaluated
3.5 Resourceneeds
3.6 Resultsofevaluation
4. SUMMARYINFORMATION 5 Table1: Priorityareas
Table2: Controlmethods
Table3: Implementationschedule
Table4: Projectedresourcesandcosts
5. REFERENCES 6
6. APPENDICES 7 Appendix1. SitemapsandJapaneseknotweeddistributionmaps
Appendix2. Japaneseknotweedrecordingsheet
Appendix3. Formsforcollectingmonitoringdata
Appendix4. Herbiciderecords
Appendix5. Wasterecords
Appendix6. Usefulcontacts
AppendixVI
Briefdescriptionoftheexistingsite(priortoanydevelopment):Includepresenceofanynatureconservation
features–e.g.protectedspecies;vegetationtoberetained;watercourses(includeproximityofstreamsorriversif
adjacenttothesite);buildingstoberetained;drainageonsite;otherrelevantfeatures.
Briefdescriptionoftheproposeddevelopment:Includeanyproposedimportorexportofsoils.
Briefdescriptionofthesitepost-development:Includeanypartsofthesitedesignatedforlandscaping,
conservationareasetc.
1.1 Description of the Site
Introduction to the site DRAFT TEMPLATE
The site is a brown-field industrial site formerly a textiles factory which has been vacant for 10 years. Buildings were demolished some 8 years ago. The site covers an area of approximately 6.5 ha. and is surrounded by mature hedgerows with some mature trees. A watercourse runs along the southern boundary of the site in an westerly direction. Existing vegetation cover is rough ruderal vegetation with several patches of Japanese knotweed within the site and adjacent to the watercourse.
The development will require site levelling, construction of a service road, installation of drainage and services and the construction of a building. Some material will be exported and the remaining inert material will be used on-site in construction works. Import of top soils for landscaping around car parking and communal areas will be required.
The proposed development will incorporate 3 sports pitches and a car parking area with a club house and facilities to the north eastern corner. A service road will provide access onto the site. Hedgerows to be retained and landscaping to be carried out in the vicinity of the clubhouse. A conservation area to the southern boundary is proposed alongside the watercourse.
Briefdescriptionofsitemanagementobjectives:Includeproposedtimescaleandplansforrestoration/re-planting.
1.2 Site Management Objectives
The site is expected to be operational 24 months after works commence. Landscape planting and restoration of the boundary hedgerows and riparian vegetation will be carried out during the construction period.
Introduction to the site DRAFT TEMPLATE
DescriptionofhowthepresenceofJapaneseknotweedposesathreatto,orlimitsmanagementobjectives.Includeforexample: • Increasingcostsofdevelopment
• Delaysinschedulingofworks
• Damageorpotentialdamagecausedbytheplant
• PotentialforspreadofJapaneseknotweedfromwithinandoutsidethesiteboundary
(e.g.withinthesite,fromadjacentlandorviawatercourses)
• PotentialforimportofJapaneseknotweedonmaterials
1.3 Limitations and Threats to Site Management Objectives
The presence of Japanese knotweed on site will increase the financial burden on this project both in terms of treatment costs and in delays in scheduling construction works. Any Japanese knotweed left untreated has the potential to damage hard surfaces and sports pitches and to delay the landscaping. A large area of Japanese knotweed exists outside the site to the eastern boundary and there is potential for further spread into the site along the watercourse. The development will necessitate the export of some material and the import of top soils for landscaping and for sports pitches. Materials leaving or brought onto site should be checked to ensure that Japanese knotweed does not leave or enter the site via this route.
Descriptionofthesiteboundaries,topography,access,specialfeatures:Includemapsofsitepreandpost
developmentinAppendix1.
DescriptionoftheJapaneseknotweeddistributiononsiteandadjacenttothesite:IncludedetailedmapsshowinglocationofJapaneseknotweedandexactareacovered(allocateauniqueidentification
numbertoeachlocationofJapaneseknotweedonsitee.g.JK001,JK002etc).
Completearecordingsheetforeachlocation(seeAppendix2)IfJapaneseknotweedispresentonadjacentland,record
distributionanddetailsoflanduseandlandownership.
1.4 Inventory of the Site
The site is reasonably level with access from the B4452 on the western boundary. The site slopes down steeply towards the watercourse on the southern boundary and there is potential in this area to accommodate a conservation area. Two mature Willow trees are located in the south western corner of the site.
Boundaries to the northern, western and eastern edges of the site are composed of mature hedgerow species including Hawthorn, Field maple, Blackthorn with some mature Ash and Oak trees.
There are 6 distinct patches of well established Japanese knotweed on the site in addition to 2 areas where a few stems have become established. These are described in the accompanying maps and recording sheets. On adjacent land to the east of the site, a large area of Japanese knotweed is present adjacent to the watercourse. Total area of Japanese knotweed on site is estimated at 1,900m2. Total area of Japanese knotweed on adjacent land is estimated at 500 m2.
58 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites59
Descriptionofmethodstobeemployedtopreventfurtherspread:Includeforexample: • IsolationofJapaneseknotweedonsitebyfencingtoavoiddisturbanceduringtreatment.
• Assessmentofriskofre-invasionofJapaneseknotweedfromadjacentland.
• LiaisonwithadjacentlandownerstotreatJapaneseknotweedwhichposesarisktothesite.
• ProcedurestoensurethatimportedmaterialsarefreefromJapaneseknotweed.
• Identificationofdesignatedhaulroutesthroughsitetoavoidcontamination.
Descriptionoftrainingtobegiventositeoperatorsandcontractorsduringdevelopment:Includeforexampleidentificationoftheplant(bothaboveandbelowgroundparts)andtrainingonsitepracticesto
preventfurtherspread.
2.3 Preventing Further Spread
Overview of weed management planOverview of weed management plan DRAFT TEMPLATE DRAFT TEMPLATE
AllocatepersonneltooverseeJapaneseknotweedmanagementandtoberesponsibleforsign–offattheendofthetreatmentperiod:
2.1 Brief Description of Management Plan
The Management of Japanese knotweed on site shall be overseen by the site foreman and in his absence, his deputy. This Management Plan and appendices and revisions of this plan shall be kept for future site owners. This Management Plan should be read in conjunction with the Environment Agency Code of Practice.
Examples: • AreasofJapaneseknotweedonsitewhichrequirerapidtreatmentwillbeidentified.
• Preventionoffurtherinfestationoftheplantonthesiteisapriority.
• Replacementvegetation/habitatwillbeconsideredratherthanjusteliminatingJapaneseknotweed.
• Controlmethodswhichsuitthelocationandtimescalewillbeadopted.
• Implementationwillbebasedontheaboveinformation.
• Regularmonitoringwillbecarriedout.
• Managementwillberevisedinresponsetofeedbackfromtheabove.
Assignprioritytoeachmanagementobjective:(e.g.High,MediumLow)-Recordprioritiesforeachlocationofthe
plantinTable1.
2.2 Setting Priorities
High Priority• Areas of Japanese knotweed which require rapid treatment - JK002 on site access route JK004 overlying site drainage route JK005 and JK008 on land proposed for sports pitches.
• Prevention of further spread. All Japanese knotweed areas to be isolated prior to any work being carried out on site. This to include an area of at least 7 m laterally from above ground stems to ensure that any underground parts are also isolated.
• All personnel on site to receive training on identification of Japanese knotweed both above and below ground parts.
Medium Priority• Control Methods for remaining areas of Japanese knotweed. A range of control methods will be adopted to include excavation and stock piling for future treatment (bund method), in-situ herbicide treatment and a combination of digging and subsequent herbicide application (combination method). Herbicides will be selected which are suitable for site use e.g. restrictions on herbicides which can be used in or near water.
• Monitoring - A scheme for monitoring will be agreed with the site foreman who will be ultimately responsible for overseeing the control of Japanese knotweed on site.
• Management - This management plan will be reviewed on a regular basis and in any case every 6 months from site acquisition to site completion.
Low Priority• Replacement vegetation. JK003 adjacent to watercourse once eliminated should be replaced with grass cover to prevent bankside erosion.
All areas affected by Japanese knotweed to be fenced and isolated from activities on site immediately to avoid potential for spread on-site. An area including a perimeter of at least 7m from the above ground stems should be isolated. See Environment Agency Code of Practice 2.1, 2.2
There is a high risk of invasion from neighbouring land. Contact the landowner and agree on a co-ordinated treatment programme.
No material to leave the site from the isolated Japanese knotweed areas.All topsoil and materials brought onto site to be checked prior to accepting. See Environment Agency Code of Practice 2.3No new materials to be stored adjacent to Japanese knotweed isolated areas.
No movement of Japanese knotweed contaminated material across site unless on designated haul routes, avoiding Japanese knotweed isolated areas.
All contractors and site operatives on site to receive training in Japanese knotweed identification and site practices. Training to be given on day 1. Posters highlighting the key features of the plant to be displayed in all communal areas (see Environment Agency Code of Practice Appendices I-IV).
60 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites61
Sitename:
Responsiblemanager: Dateplanlastupdated:
Establishmeasurableobjectivesfortheplannedcontrolactivities.Include: • theimpactondensity,cover,etc.thatyouwanttoachieve;
• thesizeoftheareainwhichyouhopetoachievethis;
• theperiodinwhichyouhopetoachieveit.
Examples: Objective1. EliminationofJapaneseknotweedonallpartsofthesitewithin5years.
Objective2. Reducepercentagecoverby50%on1haofthesitewithin2years.
Objective3. PreventionoffurtherspreadofJapaneseknotweedonsite.
Objective4. Co-ordinationwithadjacentlandownerstocommenceactivetreatmentofJapaneseknotweedin
adjacentareaswithin1year.
3.1 Management objectives (measurable)
Summary informationSpecific control plans for Japanese knotweed
3.2 Management options - (continued)
DRAFT TEMPLATE DRAFT TEMPLATE
Dummy Site
Site Foreman May 2006
Objective 1
• Immediately contain existing Japanese knotweed on site and prevent further spread.
Objective 2• Reduce the percentage cover of Japanese knotweed on site by 50% within 1 year.
Objective 3• Liaise with adjacent landowner to commence active treatment of Japanese knotweed within 1 year.
Objective 4• Eliminate Japanese knotweed on site within 4 years.
Excavation and removal off site is a rapid method of removal but is costly, and in the long term unsustainable. The particular site conditions do not allow for excavation and burial on site to the required depth of 5m (see Environment Agency Code of Practice). As there is sufficient space on site, excavation and stock-piling on site for subsequent herbicide treatment (the bund method) is a viable option particularly for those areas of site which are required to have immediate availability (e.g. access road). The remaining areas of Japanese knotweed could be treated by a combined digging and herbicide treatment or by in-situ herbicide treatment. The range of herbicides available are limited in the case of the affected areas adjacent to the watercourse, but other herbicides could be considered in more open areas away from water and mature trees. It may be necessary to vary the herbicide used or the mode of application once treatment has commenced. This should be discussed and agreed with the approved contractor.
Brieflydescribethelocationstobetreated,materialsandmethodstobeused,andanapproximatescheduleforcontrolandmonitoringactivities.RecorddetailsinTable2.
3.3 Actions planned (treatments and monitoring) - (continue on next page)
Viablecontroloptionsare: • Notreatment;
• Treatmentalternative1
• Treatmentalternative2etc.
Brieflydiscussthealternatives,indicatewhicharepreferredandtheconditions(sizeofareatreated,location,timing,
totalanticipatedcost,etc.)underwhichtheymaybeused.
Buildinrestrictedflexibilitytoallowconditionsonsitetobetakenintoconsideration.Statewhothesiteoperatives
shouldcontactwhennoneofthelistedalternativescanbecarriedout.
3.2 Management options - (continue on next page)
The various options for the control of Japanese knotweed include in situ herbicide treatment, combined treatment of digging and herbicide, excavation and stock-piling for future treatment (the bund method), excavation and burial on site or excavation and removal off site. It is not an acceptable option to consider doing nothing.
JK002, JK004, JK005, JK008Control Method: The Bund Method (See Environment Agency Code of Practice 5.4)
• Treat affected area with an appropriate non-persistent herbicide and leave for at least 1 week.
• Cut and remove canes and leave to dry on site for subsequent burning.
• Rake the surface of the affected area with tines to remove crowns and surface material – either leave to dry with canes for burning or spread on top of completed bund.
• Excavate affected area until all rhizome material has been removed.
• Create bund on a layer of geotextile starting with least infected soil and build up to 0.5 m to 1 m in height laying crown material and/or stems on top.
• Treat regrowth with appropriate herbicide.
• Disturb bund after one or two treatments and treat regrowth with appropriate herbicide.
• Continue to treat and disturb until no further regrowth appears.
• Soil from the bund may not be used off-site.
62 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites63
Summary informationSpecific control plans for Japanese knotweed
Table 1 - Priority areas
Area Descriptionandjustificationsofpriority Prioritylevel
DRAFT TEMPLATE DRAFT TEMPLATE
Brieflydescribethelocationstobetreated,materialsandmethodstobeused,andanapproximatescheduleforcontrolandmonitoringactivities.RecorddetailsinTable2.
3.3 Actions planned (treatments and monitoring) - (continued)
Estimatetheamountoftimeforstaff,materials,contractorsetc.andmoneythatwillberequiredtocarryouttheplannedcontrol,monitoringandevaluation.RecordinTable4.
3.5 Resource needs
Thissectionistobefilledinlater,preferablywithin1year,whenmonitoringdatahasbeentakenandevaluated.Theevaluationshouldbeusedtodeterminewhetheranyofthesections3.1-3.5aboveshouldbemodified.
3.6 Results of evaluation
JK001, JK006 - Control Method: Combined Treatment Method (See Environment Agency Code of Practice 3.4)
• Cut and remove canes and leave to dry on site for subsequent burning.
• Rake the surface of the affected area with tines to remove crowns and surface material and burn with canes.
• Cultivate affected area to a depth of at least 50 cm depending on the depth to which the bulk of rhizome material exists.
• Re-spread the excavated material over the cultivated area
• Apply appropriate herbicide to regrowth.
• Check for new growth at 4 - 6 weeks intervals after treatment and re-treat accordingly.
• Repeat cultivation and herbicide application until no further regrowth appears.
JK003, JK007 - Control Method: Application of herbicide to above ground stems in situ using a herbicide approved for use in or near water e.g. glyphosate (See Environment Agency Code of Practice 3.2, 3.3)
• Cut and remove dead canes during winter for subsequent burning.
• Apply herbicide according to the manufacturers guidelines.
• Check for new growth at 4 - 6 week intervals after treatment and re-treat accordingly.
Outlinethemethodsthatwillbeusedtomonitorcontrolactivitiesandthecriteriathatwillbeusedtoevaluatesuccessorfailureoftheprogram.Thecriteriaforsuccessshouldbebasedontheprogram’sobjectivesand
goals.(DatasheetstobeusedwhencollectingmonitoringdatashouldbeincludedinAppendix3).
3.4 How actions will be evaluated (criteria for success)
Monitoring will be carried out by the contractor and the site foreman prior to any treatment being carried out to act as a baseline for future monitoring and every 4 – 6 weeks throughout the growth season. The contractor and site foreman will agree the level of control achieved and the future treatment schedule. Recording sheets will be used to document the percentage cover of Japanese knotweed at each affected area on site over at least 3 representative samples of 1 m2.
JK002, JK004,JK005, JK008
JK002 on proposed access road,JK004 overlying site drainage route.
JK005 and JK008 on land proposed forsports pitches. Rapid treatment required
High
JK001, JK003,JK006, JK007
Stands on or adjacent to site boundariescan be treated in-situ Medium
Table 2 - Control Methods
Area ControlMethod Carriedoutby
JK003 ContractorHerbicide application
JK007 ContractorHerbicide application
JK008 Site operativesand contractor
Bund method
JK006 Site operativesand contractor
Combination treatment
JK005 Site operativesand contractor
Bund method
JK004 Site operativesand contractor
Bund method
JK002 Site operativesand contractor
Bund method
JK001 Site operativesand contractor
Combination treatment
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Summary information DRAFT TEMPLATE
Attachcopiesofthemap(s)ofthesite,andofmapsdepictingtheextentoftheJapaneseknotweedonthesite.
Appendix 1 - Distribution maps
Appendices
References
Listreferencescitedorused.Forexample:
Child,L.E.andWade,P.M.(2000)TheJapaneseKnotweedManual.PackardPublishingLimited,Chichester.ISBN1853411272
EnvironmentAgencyandCornwallCountyCouncil(1998)Japaneseknotweed.Howtocontrolitandpreventitsspread.EnvironmentAgency,Bodmin.
EnvironmentAgencyandCornwallCountyCouncil(2001)Japaneseknotweed.Guidanceforhouseholdersandlandowners.CornwallCountyCouncil.
WelshDevelopmentAgency(1998)ThecontrolofJapaneseknotweedinconstructionandlandscapecontracts:Modelspecification.FormerWelshDevelopmentAgency,nowpartoftheWelshAssemblyGovernment.
WelshDevelopmentAgency(1998)TheeradicationofJapaneseknotweed:Modeltenderdocument.FormerWelshDevelopmentAgency,nowpartoftheWelshAssemblyGovernment.
DRAFT TEMPLATE
DRAFT TEMPLATE
Table 3 - Implementation ScheduleScheduletheplanning,surveying,andtreatmentforJapaneseknotweedforatleastthenextyear.
TreatmentSchedule-BundMethod Date
Table 4 - Projected resources and costsRevisethistableannuallyaftercomparingestimatedtoactualcosts.
Item Description Projectedresources Projectedcosts ActualCosts
Chemical treatment to be carried outprior to excavation if plants are in leaf. day.month.year
Excavate Japanese knotweed and surrounding areauntil all traces of rhizome are removed.
Stockpile excavated material on protective membrane for treatment.day.month.year
Chemical treatment to be carried out during growingseason (March to September). day.month.year
Apply disturbance to stockpile. day.month.year
Monitor for new growth. day.month.year
Chemical treatment to be carried out during growingseason (March to September). day.month.year
Chemicaltreatment
Contractor toapply herbicide
Materials £ £Labour £ £
66 Environment AgencyManagingJapaneseknotweedondevelopmentsites Environment AgencyManagingJapaneseknotweedondevelopmentsites67
Remarks:
ExampleofJapaneseknotweedRecordingSheet(completeanewsheetforeachareaofJapaneseknotweed).
Appendix 2 - Japanese knotweed recording sheet
Averageheightofstems
Max.stemdiameterat30cmaboveground
Vegetationcomposition
Proximitytowatercourses
Slope
>2.5m
>2.5cm
1-2.5m
1-2cm
<1m
<1cm
Mixtureofknotweed&othervegetation
Japaneseknotweedonly
SteepModerateFlat
Sitename:
Recordedby: Date:
Gridref: Siteref:
m m
AreaofJapaneseknotweed-NB.MarkoutlineofareaofJapaneseknotweedonsitemapandannotatewithsiteref.
no.Ifpatchmeasures<1.0m2,markas+onmapandannotatewithsiteref.no.
Yes No
Canal
Roundabout
Graveyard
Landscapedarea
Business/IndustrialHousing
Garden
Farmland
CarPark
Riverbank
Pond Seafront
Streamside
Roadverge
Woodland
Park
Shops
Other,specifyhedgerow
Dock
Railwayembankment
Wasteground
Recreationground
Publicbuildings
Landuse-Recordprimarylanduseas1andsecondaryuseas2etc.e.g.landscapedareaadjacenttoriverbankrecord
asRiverbank1;Landscapedarea2.
Attachcopiesofdatacollectionsheets.
Appendix 3 - Forms used in collecting monitoring data
Attachdetailsofherbicidesused,doserateandapplicationratesanddatesapplied.
Appendix 4 - Herbicide records
AttachdetailsofwasterecordsforanymaterialcontainingJapaneseknotweedtakenoffsite.
Appendix 5 - Waste records
AttachdetailsofContractors,LocalAuthoritycontact,EnvironmentAgencycontact,adjacentlandownersetc.
Appendix 6 - Useful contacts
MMM
Dummy Site
XX 032 033 JK001
5 April 2006
25 18
X
X
X
X
X
1
2
large well established stand
68 Environment AgencyManagingJapaneseknotweedondevelopmentsites
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Environment first: This publication is printed on paper madefrom 100 per cent previously used waste. By-products from
making the pulp and paper are used for composting and fertiliser, formaking cement and for generating energy.
Would you like to find out more about us,or about your environment?
Then call us on 08708 506 506 (Mon-Fri 8-6)
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EA Japanese Knotweed Cover SETUP 12/9/06 5:21 pm Page 4