The U.S. Bureau of Land Management estimates millions of acres of both public and private land are currently overrun by noxious weeds, which creates an unbalanced ecosystem. Weeds are quickly overtaking forests, stream-banks, areas along bodies of water and woodlands. The noxious weeds easily destroy wildlife habitat, threaten wildlife food supplies and kill or seriously threaten native plant life.
Common crupina (Crupina vulgaris Cass) is a serious threat in California, Oregon, Idaho and Washington. The plant has a weedy, invasive nature. The weed is native to southern Europe. It grows as a winter annual and attains heights of up to 4 feet. Flowers are tiny pink or purple blossoms produced form May until early to mid-summer. The plant produces an abundance of seeds. The weed poses a serious danger to the natural environment of pasture lands, woodlands, canyons and riparian regions (areas along bodies of water).
Shrubby Russian Thistle
Shrubby Russian thistle (Salsola vermiculata L.) is a tumbleweed in appearance that poses a problem in California. The weed was introduced from Russia into the United States in the 1880s, according to the National Park Service. The weeds quickly spread across the western states and began to pose a serious problem for farmers and ranchers. The plant is an annual that grows 4 feet high and 4 feet wide. It produces small flowers that quickly begin to form seeds. Once seeds are formed, the plant dies and detaches form the stem to tumble in the wind and widely disperse more seeds.
Sticky snakewort (Ageratina adenophora) is considered to be a serious threat to native plants within California. The weed is a perennial herb that is often called Crofton weed and belongs to the same family as daisies. The plant produces white flowers and vast quantities of seeds. The weed also propagates by the spread of runners to neighboring areas. Its numerous woody branches produce small flowers followed by seeds. The weed is toxic if consumed by horses and will easily result in the animal's death later in life. When a horse consumes the weed, it is considered to have "blowing disease," which might take many years before symptoms are exhibited. The horse eventually will have edema, difficulty breathing, and hemorrhaging, according to the California Invasive Plant Council.
The southern threecornerjack (Emex australis Steinh.) is a problem in California. The plant is native to southern Africa, where it grows as a terrestrial noxious weed. The plant produces spiny fruits that are widely distributed by sticking to things such as clothing and fur. The weeds infest cultivated fields and pastureland with ease. It also easily takes over vineyards. The sharp spines can injure the feet and hooves of both domestic animals and wildlife.