Yellow starthistle (Centaurea solsitialis)



  • Yellow Starthistle Plant 215x150

Category A Weed

Sunflower family (Asteraceae)

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Stem

  • Stiff, wiry, 1-6 ft. tall and usually branched; wings (less than 0.2 in. wide) extend down stem

    Leaves

    • Blue- to gray-green, 1.5-6 in. long and densely covered with fine hairs

    • Rosette leaves are oval to strap-like (linear) with deeply lobed edges (margins); stem leaves are alternate, strap-like to oblong with smooth to wavy edges

      Flower

      • Yellow, located singly at branch tips or axils; base of flower is vase-shaped, 0.5-0.75 in. diameter and covered with cotton-like hairs and stout, straw-colored spines 0.5-1 in. long

        Root

        • Deep taproot

          Other

          • Often infests rangeland, pastures, cultivated fields, waste areas and roadsides; known to occur in Carson City, Churchill, Douglas, Elko, Humboldt, Lander, Lyon, Mineral, Pershing, Storey and Washoe counties

          • Annual; reproduces by seed

          • Causes "chewing disease" in horses by damaging the area of the brain that controls fine motor movements, particularly of the mouth, resulting in starvation or dehydration

            Control

            • Grazing, mowing, burning, pulling, digging and cultivation can be effective if done prior to seed production

            • Several biological control agents are available

            • Apply aminopyralid, 2,4-D, clopyralid, dicamba or picloram to actively growing plants before flowering

              Images

              Yellow Starthistle Plant 215x150
              Plant
              Yellow Starthistle Rosette 215x150
              Rosette
              Yellow Starthistle Flower 215x150
              Flower
              Yellow Starthistle Infestation 215x150
              Infestation
              Yellow Starthistle Leaf 215x150
              Winged Stem
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              Nevada Noxious Weed Guide