Perennial Sowthistle (State designated weed)

Perennial Sowthistle

  • Sonchus arvensis
  • Asteraceae (Sunflower family)

Perennial sowthistle is a native of Europe or Eurasia, now widely distributed in North America, and considered noxious in many states and provinces. It is common in gardens, cultivated crops, ditchbanks, and fertile waste areas where adequate water is available. It reproduces by seed and roots.

Growth Habit: Perennial, erect, slender plant up to 4 feet tall.

Leaves: Prickly serrations on margins, may be deep lobed, narrow at base. Upper leaves clasp stem. Alternate, usually crowded on lower half of stem. Stems produce a milky substance when broken.

Flower: Bright yellow, flat topped, clustered, 1 to 2 inches in diameter, resembling a dandelion.

Roots: Creeping horizontal roots, give rise to new shoots at joints. Yellowish white with milky juice.

Status: State Designated Noxious Weed, Category 4 Fremont County. Widespread infestation, control and maintenance of current weed infestations.

Control: Chemical controls are effective. FCWP offers a 40 percent Cost Share on chemicals for controlling this species. Contact your local weed and pest office for further treatment recommendations.

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Lander, WY 82520


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