Canada Thistle

Cirsium arvense

  1. A perennial thistle with tap root and extensive creeping root system; grows in patches which can spread quickly; plants are either male or female.
  2. Grazing (early season); timed herbicide control with selective Group 4 herbicides; mowing repeatedly to prevent seedset and deplete root reserves; biological controls released but are largely ineffective.
  3. Identification Guide for Alberta Invasive Plants
    Weeds of the Prairies
    WeedsBMP App BC – iOS | Android