Cassie L. Conner, Coordinator Sandhills Weed Management Area

Southern Pines, NCcassieconner@sandhillswma.org

http://www.sandhillswma.org

Bad Neighbors:How Invasive Plants Threaten Natives

What is the Sandhills Weed Management Area?

The Sandhills Weed Management Area (SWMA) is a cooperative weed management area which the Midwest Invasive Plant Network defines as:

“…a local organization that integrates all invasive plant management resources across jurisdictional boundaries in order to benefit entire communities.”

This means….

Cooperative Weed Management Areas

• Organizations working together

• Sharing resources

• Transcending property boundaries

How Do Invasives Impact Natives?

They use limited

resources such as

space, light, water and nutrients

needed by native plants.

How Do Invasives Impact Natives?

Some actively smother or strangle otherplants.

How Do Invasives Impact Natives?

Some are allelopathic – their roots exude a chemical that prevents the germination of the seeds of other plants. Spring ephemerals are especially susceptible.

How Do Invasives Impact Natives?

They change the natural biomass

load and nutrient cycle of areas they invade.

How Do Invasives Impact Natives?

They hybridize with native, and

sometimes rare, populations.

Chinese privet – Ligustrum sinenseSpecies Profile

Growth form: Chinese privet is a shrub or small tree growing between 5 to 12 feet

Flower: Flowers occur in cone-shaped, branching clusters two to four inches long that profusely cover the shrub. The flowers produce a somewhat disagreeable aroma

Seeds/Fruit: Flowers mature into bluish black, berry-like fruits.

Leaves: Leaves are evergreen to semi-deciduous and oppositely arranged on nodes usually less than one inch apart.

Stems: Chinese privet branches abundantly and the branches typically arch gently downward.

Roots: The root system is shallow but extensive. Suckers are readily produced.

Lowell Urbatsch @ USDA-NRCS PLANTS Database

Chinese Privet Control

Chinese privet is difficult to control because of the huge seedbank and the need to remove underground parts as well. Small infestations in the early stages of invasion can be controlled mechanically by removing the entire plant. Fire is an ineffective control method. Herbicide application has been shown to be an effective control method. Foliar spray application of herbicide can be used on large thickets where damage to nearby species is not an issue. Cut stump and basal bark treatments are effective as long as the ground is not frozen.

SWMA recommendations:• Small plants in loose soil can be pulled as long as entire plant and

root system are removed• Small plants that cannot be pulled can be treated with a 2%

glyphosate foliar spray• Large shrubs should have their stems cut and a 20% glyphosate

mixture should be applied to the cut stump

English Ivy – Hedera helixSpecies Profile

Growth form: English ivy is an evergreen climbing vine or groundcover. It can attach itself to almost any surface and grow 80 feet high. As a groundcover it can spread 50 feet wide.

Flower: Small, greenish-white flowers appear on mature plants. They occur in umbrella-like clusters in the fall.

Seeds/Fruit: A black, berry-like drupe, ¼ inch across matures in the spring and ripens over winter.

Leaves: Leaves are alternate, simple, dark green, waxy and somewhat leathery with many recognized leaf forms. The most common form being a 3 to 5 lobed leaf with a heart-shaped base.

Stems: The stems of older vines are known to reach a foot in diameter. The stems root as they spread outward.

Roots: Small roots grow from the stems and attach to many things with a glue-like substance.

(Swearingen 2000)

(VTU 2002)

English Ivy Control

H. helix originates from landscape plantings. To prevent initial introduction, native alternative vines should be used in plantings. To control established invasions, the use of herbicides is most effective. Combining the use of cutting and herbicide application is very effective.

Native vine alternatives: Trumpet Creeper (Campsis radicans), Virginia Creeper (Parthenocissus quinquefolia), Passionflower Vine (Passiflora lutea), Dutchman's Pipe (Aristolochia macrophylla), and native Wisteria (Wisteria frutescens).

SWMA recommendations:• Small plants in loose soil can be pulled as long as entire plant and root

system are removed• Small plants that cannot be pulled can be treated with a 2% glyphosate foliar

spray• Large vines should be cut near the ground and a 20% glyphosate mixture

should be applied to the cut stump

Chinese Silvergrass – Miscanthus sinensisSpecies Profile

Growth form: Tall, densely bunched, perennial grass, 5 to 10 feet (1.5 to 3 m) in height.

Flower: Much branched and drooping terminal plumed panicles. Silvery to pinkish, showiest in fall.

Seeds/Fruit: Many loosely plumed panicles in late summer turning silvery to pinkish in fall.

Leaves: Long-slender upright-to-arching leaves with whitish upper midveins.

Stems: Upright-to-arching, originating in tufts from base and unbranched. Covered with overlapping leaf sheaths until stem appears with flower plume in late summer.

Roots: Has a a branched, subterranean rhizome system by which it can reproduce.

Chinese Silvergrass Control

Chinese Silvergrass reproduces primarily through an extensive underground rhizome system. A piece of its rhizome as small as 4cm can be used to propagate the plant. It is also known to move into areas that have been burned or cut. In addition to this, it is highly flammable and can increase the intensity of a fire as well as to encourage the spread of the fire when wind picks up burning pieces of its debris. Therefore it is not recommended that it be treated with fire. Chemical control can be successful particularly in the fall with repeat applications. A repeated combination of mowing and chemical control has proven effective.

NPS recommendation:

Large areas of Chinese Silvergrass can be mowed and then allowed to resprout to the height of 1 ft. Then apply a foliar spray of 2-3% glyphosate mixture.

Garlic Mustard – Alliaria petiolataSpecies Profile

Growth form: Alliaria petiolata is an obligate biennial herb. Seedlings emerge in spring and form basal rosettes by midsummer. Immature plants overwinter as basal rosettes. In the spring of the second year the rosettes (now adult plants) produce flower stalks, set seed, and subsequently die.

Flower: April to May. Terminal, tight clusters of small white four-petaled flowers

Seeds/Fruit: Green ripening to tan and papery, exploding to expel tiny black seeds up to 10ft.

Leaves: Early basal rosette of kidney-shaped leaves and later alternate heart-shaped to triangular leaves.

Stems: Erect, slightly ridged, light green, hairless above and hairy below. One to several stems from the same rootstock.

Garlic Mustard Control

Garlic Mustard’s success as an invasive is due to it’s ability to produce an extensive number of seeds. A single plant can produce thousands of seed that remain viable in the seedbank for at least 5 years. Any successful control will require a commitment to treat the site at least annually for several years. Mechanical removal such as pulling, cutting or mowing before the plant goes to seed can be successful, as can chemical control if applied before the plant goes to seed.

SWMA recommendations:

• Small infestations should be hand pulled before the plant sets seed.• Larger, accessible sites should be mowed.• Large, hard to access sites should be treated with a foliar application of

2% glyphosate• Plants with flowers or seed capsules should be bagged and removed

from the site to avoid spreading seed.• All management plans should include treatment over multiple years

until the seed bank is exhausted.

Kudzu - Pueraria montanaSpecies Profile

Growth form: Semi-woody, aggressively climbing perennial vine that is capable of growing a foot per day, extending 60 feet a year, and reaching up to 100 feet in length.

Flower: Sunlit kudzu produces rare blooms of elongate hanging racemes that contain clusters of pea-like purple flowers

Seeds/Fruit: Brown, papery, hairy, flat seed pods that contain three to twelve small, hard, rounded seeds.

Leaves: Dark green, deciduous leaves are alternate and pinnately trifoliate

Stems: Thick, rough, bark-covered stems have long, yellowish brown hairs at the base

Roots: Edible fibrous tubers can grow to over seven inches wide and six feet long, and weigh 400 pounds, with each root crown capable of forming thirty vines.

Kudzu Control

Kudzu should be cut or mowed late in the growing season and the plant material should be removed from the area and destroyed. Herbicide should be applied to the cut stems. The type of herbicide used depends on the landscape and its uses. Burning after the herbicide has killed the Kudzu may assist native plants in colonizing the site. This procedure will need to be repeated for 4-10 years.

SWMA Recommendations:• Cut vines of climbing or trailing kudzu until a root crown is found.

Dig up root crown with a mattock and spray with a 20% glyphosate solution.

Oriental Bittersweet – Celastrus orbiculatusSpecies Profile

Growth form: Deciduous, twining and climbing woody vine to 60 feet (20 m) in tree crowns, forming thicket and arbor infestations.

Flower: Axillary dangling clusters of inconspicuous yellowish flowers in spring.

Seeds/Fruit: Green spherical fruit that split to reveal three-parted showy scarlet berries in winter.

Leaves: Alternate, elliptic to rounded leaves. Variable shaped, long tapering tipped when young becoming larger and round tipped when mature.

Stems: Woody vine to 4 inches (10 cm) diameter, twining and arbor forming, with many alternate drooping branches growing at angles and eventually becoming straight.

Oriental Bittersweet Control

Oriental Bittersweet is a widespread and prolific invasive due in part to it’s commercial use by humans. It is particularly difficult to control because of it’s lack of response to common herbicides like glyphosate. Weekly mowing can be an effective control, but less frequent mowing will stimulate root suckering. Manual pulling has been effective on small infestation and a combination of cutting and herbicide application has been effective in controlling large populations. If seeds are present on pulled or cut plants, they should be bagged and removed from the site to prevent further seedbank establishment.

SWM recommendations:• Small plants in loose soil can be pulled as long as entire plant and root

system are removed• Small plants that cannot be pulled can be treated with a 2% tricolpyr foliar

spray• Large vines should be cut near the ground and either immediately treated

with a 25% triclopyr solution or allowed to resurge for a month and then treat the regrowth with a 2% triclopyr foliar spray

Invasive NativeOriental Bittersweet vs. American Bittersweet

(Celastrus orbiculatus) (Celastrus scandens)

American Bittersweet is threatened by Oriental Bittersweet – hybridization

• Fast grower • Slow grower

• Flowers and fruit present all along stems

• Flowers and fruit present only at the end of stems

• Smaller fruit, 5 or more seeds

• Larger fruit, 1 or fewer seeds

• When first leafing out, the two sides of the leaf are folded together

• When first leafing out, the leaf margins are rolled under like a scroll

Invasive NativeOriental Bittersweet vs. American Bittersweet

(Celastrus orbiculatus) (Celastrus scandens)

Oriental Bittersweet – North Carolina Class C Noxious Weed

• NC has three classes of noxious weeds; A,B and C• Class A plants are prohibited from being sold,

distributed or moved into or within North Carolina- includes all federally-listed weeds plus 5 others

• Class B plants are prohibited from being sold, distributed or moved out of counties under quarantine - includes 9 species

• Class C plants are prohibited from being moved out of counties under quarantine, BUT sale and distribution is allowed– Oriental Bittersweet is the ONLY plant in Class C

Summer ED/RR Field Team

• An Early Detection/Rapid Response approach allows land managers to quickly address new invasive plant problems

• The SWMA Field

Team worked on

six different sites

for four partnership

members

SWMA Website:http://www.sandhillswma.org

Website Features

• A native plant list with suggestions for alternatives to invasives

• Species profiles• Species distribution lists• Photos for learning identification• A message board for community interaction• Links to other invasive management resources• Past presentation and other outreach material

Benefits of a CWMA

Resource Sharing

Physical Resources

-Tools

- Herbicide

- Equipment

- Storage

Benefits of a CWMA

Resource SharingHuman Resources

- One coordinator or leadership committee for all areas

- Expertise of land managers, biologists, botanists, etc. from all partner organization

- Field team available for use in all areas

Benefits of a CWMA

Transcending Boundaries

Weeds don’t obey property lines

- Infestations may stretch across

jurisdictional boundaries

- Populations in adjacent areas

may infest high quality area

Benefits of a CWMA

Managing a Large Area• Assessing new species for Early Detection/Rapid

Response consideration• Prioritizing control activities

- Examples of high priority sites Infestations of new

invasive species with

potential to spread Infestations in or near

high quality sites