|
Species
Information
- plumeless thistle
- Carduus
acanthoides
L.
- USDA
Symbol: CAAC
- Oregon
Noxious Weed Designation: A
- Pictures
ALERT: PLEASE CALL 1-866-INVADER IF YOU SUSPECT YOU HAVE FOUND THIS SPECIES
Identification: Winter annual or biennial herb; flowers May to July. Grows 1 to 4 feet tall. Stems covered with spiny wings. Rosette leaves 4 to 8 inches long, stem leaves alternate and blend into the stem. Flower heads in clusters of 2 to 5 and usually purple but can be yellow or white.
The only known populations of plumeless thistle in Oregon are in Grant county.
Impacts: Plumeless thistle grows in pastures, stream valleys, fields and roadsides. Though distribution in Oregon is very limited, it has the potential to become a widespread noxious weed.
Biological
Controls: Biological control agents are not used on "A" listed weeds in Oregon. If this weed is found in the state it will be managed for eradication or containment. There are two approved biocontrol agents for use in other states: a seed head weevil and a crown weevil.
Oregon
Maps of Plumeless Thistle Distribution
Links:
USDA
Plants Database information on plumeless thistle
GRIN
Database information on plumeless thistle
Oregon Department
of Agriculture information on plumeless thistle
|
