• Musk Thistle Plant 215x150

Category B Weed

Sunflower family (Asteraceae)

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Musk thistle (carduus nutans)

    Stem

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

      Leaves

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

        Flower

        • 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

          Root

          • Deep, fleshy taproot

            Other

            • 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

              Control

              • 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