Canada Thistle


Canada Thistle (Cirsium arvense) Sunflower family

Not yet found in Fairbanks area - Report immeddiately if found! Call 479-1213

A perennial that grows to five feet tall with erect, ridged branching stems. Leaves have sharp spines, are wavy, oblong, alternate on stem with woolly hairs on underside.Leaves arise directly from the stem without a distinct leaf stalk. Flowers are purple-pink in clusters at the ends of branches.

Forms colonies via an extensive horizontal and vertical root system; can eventually cover acres. Also spreads by wind-blown seeds. Young plants appear as basal rosettes that bloom in late summer.

Not yet found in the Fairbanks area. Can be found in fields, pastures, forests, along roadsides, ditches, and river banks.Produces allelopathic chemicals that suppress surrounding vegetation.

More information


UAF Cooperative Extension Service U.S. Fish and Wildlife Service U.S. Forest Service National Park Service Bureau of Land Management - Fairbanks District Office Fairbanks North Star Borough - Parks & Recreation