Poison Hemlock


  • Douglas County Class B weed
  • Native to Europe, Asia and Northern Africa
  • Flowers: white, small and occur in 4 to 8 inch umbrella shaped clusters
  • Stems are hollow like bamboo and are covered with purple blotches
  • Bushy, branched perennial, usually 1 to 3 feet tall
  • Poison hemlock prefers rich, moist soil, but is highly adaptable to other conditions
  • Poison hemlock reproduces by seed
  • Other names: carrot-fern, fool's-parsley, spotted hemlock

Control Methods

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  • General Description: Poison Hemlock can quickly infest large areas of pasture as well as open waste places.
  • Caution: The entire plant is toxic to animals and humans, containing the poisonous alkaloid coniine and other alkaloids. Therefore, always wear gloves and protective clothing if handling poison hemlock.
  • Mechanical Control: Digging up small infestations and removing the entire taproot is effective. Mowing is ineffective as plants will re-sprout, sending up new stalks in the same season mowing occurs.
  • Herbicide Control: Please refer to the Pacific Northwest (PNW) Weed Management Handbook, or contact your county noxious weed coordinator or Washington State University (WSU) Extension office for additional chemical options.