Noxious Weeds
1. Houndstoungue
Appearance:
Known as houndstongue because leaves and rough surface of the nutlets resemble a dog's tongue.
Coarse, softly long-hairy, biennial herb.
Reddish-purple, shortly funnel-shaped flowers that typically bloom from May to July.
After flowering, clusters of 4 nutlets appear, covered in short, barbed pickles. These nutlets are sticky and attach to what comes into contact with them.
Why noxious?
Introduced from Europe and spread across North America.
Contains alkaloids that are toxic to grazing animals
Sticky seeds stress livestock.
Mature plants contain up to 200 seeds, wide, rapid spread.
Roots can grow as deep as 3 feet, resource competitor for native plants.
Control:
Hand pull for non-flowering plants and plant will dry out; however, this is difficult due to deep root system.
Hand pull for flowering plant and bag
Herbicide, also effective.
Picture sourced from: co.power.id.us
2. St. John's Wort
Appearance:
Found in moist, open slopes and ledges; foothills to alpine; British Columbia and Alberta to New Mexico.
Perennial herb with many stems and egg-shaped leaves on opposite sides of the stem.
Flowers are bright yellow, about 2 cm across, with 5 broad petals edged with black dots or teeth. Typically flower from July to August.
Height: 1-3 feet.
Uses:
Historically, St. John's wort has been used for a variety of conditions, including kidney and lung ailments, insomnia, and depression, and to aid wound healing.
The aerial plant is dried for a variety of uses. Fresh flowers are used in making healing oils and they can be tossed into salads. Fresh leaves can be used in salads.
Research indicates St. John's Wort is an effective remedy against depression and other nervous-related conditions.
Why noxious?:
Extensive root system, resource competitor for native plants
Hypericin is toxic for livestock and humans; can cause sores/rash
Control:
Hand pulling/digging
Mowing
Biological and herbicide
Picture source from: lgbotanicals.com
3. Spotted Knapweed
Appearance:
Found on disturbed sites in fields, roadsides, and waste places; plains to montane in western North America.
Biennial or short-lived perennial herb with rough stems, free branches, and no spine.
Leaves alternate, pinnately cut into linear segments, grey with thin, cobwebby hairs when young.
Flowers have a pinkish-purple head, about 2.5 cm across, and come in clusters above urn-shaped involucres. Typically flower from June to October.
Height up to 6 feet tall.
Why Noxious?:
Introduced from Asia in alfalfa seeds.
Stiff hairs can be harmful to the digestive tract of livestock.
Suspected to release toxins that inhibit growth of native plants.
Seed remains viable for up to 8 years; overgrowth.
Control:
Hand pulling or digging using gloves
Biological, herbicide, and mechanical controls.
Picture sourced from: wyoweed.org
4. Canada Thistle
Appearance:
Perennial herb that forms colonies from deep, spreading roots.
Have alternating lance-shaped, spiny-toothed, and deeply lobed leaves around the edges.
Flowers are pinkish-purple, 12-25 mm across, and generally bloom from July to August.
Found on disturbed sites along roads and in fields and waste places; from British Columbia and Alberta to New Mexico.
Height 2-5 feet tall.
Why Noxious?:
Introduced from Europe.
Extensive nutrient stores and root system.
Reduces livestock forage consumption.
Seeds remain viable in soil for up to 22 years.
Control:
Cutting or mowing.
Biological or herbicide control.
Re-vegetation (competing crops).
Picture sourced from: nwcb.wa.gov & Eileen Sande
5. Dalmatian Toadflax
Appearance:
Found in disturbed, cultivated or waste ground in lower elevations; plains to montane; British Columbia and Alberta to New Mexico.
Ill-scented, hairless, perennial herb resembling butter and eggs.
There are many, alternating, heart-shaped leaves that clasp to the stem with a waxy coating.
Flowers are yellow, with a fuzzy, orange lower lip, egg-like, 2-3.5 cm long, extended back in a straight, slender spur.
Introduced into the western U.S. from the Mediterranean region of Europe as an ornamental toadflax in 1874; hybridized with yellow toadflax.
Height from 2-3 feet.
Why Noxious?:
Suspected to be toxic to some animals if large quantities are ingested.
Deep, extensive root system; resource competitor for native plants.
Reduces grazing areas for livestock.
Mature plants can produce up to 500,000 seeds, which can stay viable in the soil for up to 10 years.
Control:
Biological and herbicide control (waxy leaf coating makes it difficult).
Sheep grazing.
Picture sourced from: kingcounty.gov