Canada Thistle - A rhizomatous, perennial, herbaceous plant that grows 2-5 feet tall, usually branching only near the top of the plant.
Leaves: Leaves are alternate and lance to narrowly oval in shape, possessing short spines along the leaf edges.
Flowers: Flowers bloom from May-October. Many flowerheads clustered towards the tip of the stem, purple to pink in color.
Habitat: Common in pastures and croplands. Can also invade wet areas as well like steam banks, sedge meadows, and wet prairies.
Weed Classification: C Select
Why is it a Noxious Weed?
Once established, it can spread vigorously and replaces native plants. It also lowers crop yields by outcompeting crops.
Canada Thistle is selected for control in Lewis County. If you need help identifying your thistle or need control recommendations, let us know.
WA State Noxious Weed Control Board