Plumeless Thistle

Carduus acanthoides

Family: Asteraceae

Other Common Names: spiny plumeless thistle
Weed class: B
Year Listed: 1988
Native to: Europe and temperate Asia
Is this Weed Toxic?:

not known to be

Legal listings:

This plant is also on the Washington State quarantine list. It is prohibited to transport, buy, sell, offer for sale, or distribute plants or plant parts of quarantined species into or within the state of Washington or to sell, offer for sale, or distribute seed packets of seed, flower seed blends, or wildflower mixes of quarantined species into or within the state of Washington. Please see WAC 16-752 for more information on the quarantine list. For questions about the quarantine list, contact the Washington State Department of Agriculture's Plant Services Program at (360) 902-1874 or email PlantServices@agr.wa.gov.

Why Is It a Noxious Weed?

Plumeless thistle invades pastures, meadows, and fields crowding out desirable forage plants. Livestock will not graze in areas heavily infested with plumeless thistle.

How would I identify it?

General Description

It is an upright, spiny, biennial growing up to 8 feet tall.

Flower Description

Flowers are solitary or in clusters of 2 to 3 flower heads with reddish purple flowers.

Leaf description

Dark green leaves are deeply lobed to compound with hair on the undersides and spines along the leaf margins.

Stem description

Stems are tough and have spiny wings.

Fruit Seed Description

Seeds (achenes) are smooth and hairless.

Where does it grow?

Plumeless thistle grows in pastures, stream valleys, fields and roadsides. Please click here to see a county level distribution map of plumeless thistle in Washington.