Canada thistle (Cirsium arvense)

Stem

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

Leaves

• 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

Flower

• 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

Root

• Deep, extensive creeping root system

Other

• 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

Control

• 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