Canada Thistle
(Cirsium arvense L.)

Description:
Canada Thistle is a perennial that spreads by creeping underground rhizomes. The plant also spreads by seeds which can float for long distances on the wind supported by a light brown parachute like plume. THe plants produce one to three compact lavender colored flowers at the tips of the branches. Plants are about four feet high. The leaves are long and narrow with crinkled spiny edges.

• Mechanical: Canada Thistle may need to be cut several times, during the growing season, to prevent seed production.
• Biological: A stem gall producing fly has been successful
• Herbicide: Refer to the State Noxious Weed Control Board site

For More Information:
Detailed information about Canada Thistle is available at the Washington State Noxious Weed Control Board Web Site.