Canada thistle (Cirsium arvense)

Category C Weed

Sunflower family (Asteraceae)

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  • Up to 4 ft. tall, green to brown, branched at the top and usually lacks hair (glabrous)


    • Alternate, oblong or lance-shaped, 2-8 in. long, shiny and lack hair; NO leaf stems (petioles); leaf edges (margins) are wavy, lobed or toothed with spiny edges


      • Pink, purple or white; occur in clusters at the ends of branches; base of flower is vase-shaped, 0.5-0.75 in. wide, lacks prickles and is covered with green to purple bracts with dark tips


        • Deep, extensive creeping root system


          • Grows best in moist areas; often found in pastures, hay fields, waste areas and along waterways; known to occur in all Nevada counties except Esmeralda

          • Perennial; reproduces by both roots and seed; plants often appear in patches or colonies due to the spreading root system


            • Repeated mowing, tillage, cutting or hand removal prior to seed production can provide suppression

            • Several biological control agents are available

            • Apply picloram, aminopyralid or clopyralid to actively growing plants through flowering; repeated applications of 2,4-D, dicamba or glyphosate to actively growing plants


              Canda Thistle Mature Plant
              Mature Plant
              Canda Thistle Rosette
              Canda Thistle Infestation
              Canda Thistle Root
              Canda Thistle Seed Head
              Seed Head
              Nevada Noxious Weed Field Guide
              Nevada Noxious Weed Guide