Musk thistle (carduus nutans)

Category B Weed

Sunflower family (Asteraceae)

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  • 2-6 ft. tall and sometimes wooly and branched; spiny wings caused by leaf bases that extend down the stem


    • Dark green with a light-green midvein, 4-15 in. long, alternate and sometimes hairy; edges (margins) are deeply lobed and spiny


      • Pink to purple (occasionally white), up to 3 in. wide, each located at the tip of a stem; head often nods or droops; stem below head usually spineless

      • Base of flower is covered with green, purple- or straw-colored, spine-tipped bracts; bracts are 0.1-0.3 in. wide, lance-shaped and sometimes hairy


        • Deep, fleshy taproot


          • Often infests roadsides, pastures and waste areas; known to occur in all Nevada counties EXCEPT Douglas, Esmeralda, Mineral and Pershing

          • Biennial; reproduces by seed; also known as nodding thistle


            • Mowing, tilling or hand removal after bolting but prior to flowering is effective; remove the top 2 in. of crown by digging before seed production

            • Several biological controls are available

            • Apply 2,4-D, dicamba, chlorsulfuron, metsulfuron or picloram to actively growing rosettes; aminopyralid or clopyralid between rosette and late-bolt stages


              Musk Thistle Plant
              Mature Plant
              Mayweed Chamomile Flower
              Musk Thistle Infestation
              Mayweed Chamomile Rosette
                Nevada Noxious Weed Field Guide
              Nevada Noxious Weed Guide