Weeds Mandated for Eradication by the State of Colorado

	African Rue (Peganum harmala) is a perennial that is toxic to ruminants. It is native to North African and Asiatic deserts.
	Camelthorn (Alhagi pseudalhagi) is a perennial shrub in the pea family that can grow as tall as 4 feet. It is intricately branched with spines along the stems.
	Common crupina (Crupina vulgaris) is an annual that favors southern slopes in steep canyon grasslands. The flowers are purple and the first leaves have a red or purple midvein.
	Cypress spurge (Euphorbia cyparissias) is an escaped ornamental found in Fort Collins.
	Dyer's woad (Isatis tinctoria) was introduced from Europe and has a tap root that can exceed 5 feet in depth.
	Giant salvinia (Salvinia molesta) is an aquatic weed that grows rapidly to cover waterways, possibly doubling its surface area every 5 days.
	Hydrilla (Hydrilla verticillata) is an aquatic weed that grows rapidly to cover waterways. This perennial was imported to the U.S. in the 1950s for use in aquariums. Hydrilla is mainly introduced as castaway fragments on recreational boats. Once established, boat traffic continues to shatter and spread hydrilla throughout the waterbody.
	Meadow knapweed (Centaurea pratensis) is a perennial that grows up to 3 1/2 feet tall. It infests roadsides, waste areas, fields and pastures of the West.
	Mediterranean sage (Salvia aethiopis) is a strong-smelling weed in the mint family. Some say the plant smells like horse sweat. A rosette develops in the first season and then bolts the following year.
	Medusahead (Taeniatherum caput-medusae) is an aggressive winter annual with long-awned spikes that give the plant its name.
	Myrtle spurge (Euphorbia myrsinites) is an escaped ornamental that is used in rock gardens. It escapes cultivation and invades native ecosystems. The milky latex contained within the plant is highly toxic and can cause scarring.
	Purple loosestrife (Lythrum salicaria) is a perennial weed often found in wetlands and marshy areas. This plant is found in small quantities in Colorado due to a vigorous eradication campaign. Millions of acres of precious wetlands have been rendered biologically useless due to the invasion of purple loosestrife.
	Rush skeletonweed (Chondrilla juncea) is a perennial that grows from 1 to 4 feet tall with yellow flowers. This weed was introduced from Eurasia and infests millions of acres in the West.
	Squarrose knapweed (Centaurea virgata) is a long-lived perennial that infests rangeland in the West. It is often confused with diffuse knapweed but bracts are recurved.
	Tansy ragwort (Senecio jacobaea) is a biennial or short-lived perennial with yellow, terminal flowers. The rosettes have leaves that are deeply lobed.
	Yellow starthistle (Centaurea solstitialis) is an annual that has rendered millions of acres useless to wildlife and cattle in California.
	Sericea lespedeza (Lespedeza cuneata) is a perennial legume with extensive roots. Late in the growing season, tannin accumulates making this plant unpalatable.