Lessons from WeedsA close look at non-native opportunistic plants

“Why do people want to kill plants that want to grow and grow plants that want to die?”

Weeds? Non-natives Hard working & opportunistic Indicators of soil or environmental conditions

pH, N – P – K, water, compaction

Pros and Cons? Negative contributions

Positive contributions

Contributions of hard working plants

Reduce soil erosion Mitigate soil compaction Improve soil (N fixing, biodynamic accumulation) Food source and habitat for beneficial insects Potential source of food and medicine Indicator of soil conditions

Classification review Broadleaf (dicots) Grasses (monocots)

“control” Cultural (change the environment) Physical (get down there and pull) Biological (invasivores?) Chemical (the last resort)

Being an “invasivore” Positive identification Understanding of growing conditions Free access Ethical foraging (rule of 3)

Chickweed - Broadleaf

INDICATORS: - High N - If stunted, low P, moisture

LIKELY SITES: - Shady - Fertilized CONTRIBUTION: - Food - Medicine

B, P

Stellaria media

Sow Thistle - Asteraceae

INDICATORS: - High N - neutral pH

LIKELY SITES: - Disturbed - Fertilized CONTRIBUTION: - Food, forage

Sonchus asper

Dandelion - Asteraceae

INDICATORS: - Moisture - Acidic soil

LIKELY SITES: - Disturbed - Fertilized CONTRIBUTION: Food, Medicine, Insectiary

Taraxacum officinale

Poison Hemlock - Apiaceae

INDICATORS: - Herbicide application

LIKELY SITES: - Disturbed - Fertilized CONTRIBUTION: Insectiary, Poison

Conium maculatum

Groundsel - Asteraceae

INDICATORS: - High fertility

LIKELY SITES: - Cultivated CONTRIBUTION: Medicinal, wildlife food and habitat.

1 plant = 25,000+ seeds

Mechanical

Senecio vulgaris

Nutsedge, Tigernut - Cyperaeceae - Grass (monocot)

INDICATORS: - Wet soil, poor drainage - acid pH

LIKELY SITES: - Overwatered - Neglected CONTRIBUTION: Nutritional tuber, medicinal, oil, cosmetics

Deep fragile roots

Cyperus esculentus

Mallow, Cheeseweed - Malvaceae

INDICATORS: - Deep N - Disturbed soil

LIKELY SITES: - Disturbed - Neglected CONTRIBUTION: - Food - Medicine

P, B

Malva parviflora

Nettle, Annual nettle, Small nettle - Urticaceae

INDICATORS: - Deep NPK LIKELY SITES: - Disturbed CONTRIBUTION: Insectiary, Biodynamic accumulatorMedicine, Food

Urtica urens

Pellitory of the Wall - Urticaceae

INDICATORS: - Heavy metals?

LIKELY SITES: - Neglected - the Wall CONTRIBUTION: Medicinal

Parietaria officinalis

Purslane, Verdolaga -Portulacaceae

INDICATORS: Deep moisture and soil nutrients. LIKELY SITES: - Compacted, - Cultivated sites CONTRIBUTION: Food (linoleic acid), medicinal, companion plant

Portulaca oleracea

Getting a handle on BROOMScotch broom

(Cytisus scoparius)

French broom(Genista

monspessulana)

Spanish broom

(Spartium junceum)

Portuguese broom

(Cytisus striatus)

Stems: 5-sided; star-shaped cross sectionLeaves: compound, 3 leaflets, deciduous, sometimes single on new twigs

Stems: 8 to 10 ridges; round cross sectionLeaves: compound, 3 leaflets, evergreen, usually dense

Stems: smooth or finely ribbed; round cross sectionLeaves: simple, deciduous, sparse

Stems: 8 to 10 ridges; round cross sectionLeaves: compound, 3 leaflets, deciduous, sometimes single on new twigs

Flowers at leaf axils

Flowers at branch tips

Flowers at branch tips

Flowers at leaf axils

Cytisus Scoparius SCOTCH BROOM

http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74147.html

French Broom - Fabaceae

INDICATORS: - Low N

LIKELY SITES: - Disturbed - Eroded CONTRIBUTION: - Forage, dye - Prevents erosion

Mechanical. Seeds viable for 30+ yrs

Genista monspessulana

Sourgrass, Bermuda buttercup - Broadleaf

INDICATORS: - High N - neutral pH

LIKELY SITES: - Disturbed - Available CONTRIBUTION: - Food - Prevents erosion

Oxalis pes caprae

Fred Bové Fred@fredbove.com

Gardenswithbenefits.com