Perennial sowthistle (Sonchus arvensis)


Category A Weed

Sunflower family (Asteraceae)

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Stem

  • Up to 6 ft. tall, mostly unbranched except near the top where several flower stems form; exudes white, milky sap when broken

    Leaves

    • Alternate; upper leaves are smaller and fewer than lower leaves; leaf bases clasp the stem; exude white, milky sap when broken

    • Edges (margins) smooth to deeply lobed and spiny

      Flower

      • Yellow; less than 2 in. wide; base of flower is vase shaped; flower base and stalk usually covered with stiff, sticky hairs

        Root

        • Creeping root system

          Other

          • Grows best in moist, fertile soils; often infests crop fields, gardens, waste areas and ditch banks; known to occur in Elko, Humboldt, Lincoln, Storey and White Pine counties

          • Perennial; reproduces by seed and roots; seed is wind-dispersed

            Control

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

              Images

              Perennial Sowthistle Infestation 215x150
              Infestation
              Perennial Sowthistle Plant 215x150
              Mature Plant
              Perennial Sowthistle Leaf 215x150
              Leaf
              Perennial Sowthistle Root 215x150
              Roots
              Perennial Sowthistle Flower 215x150
              Flowerhead
              Nevada Noxious Weed Field Guide
              Nevada Noxious Weed Guide