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poison hemlock

Scientific Name: Conium maculatum

Family: Apiaceae

Category: Dicot

Growth: Forb/herb

Duration: Biennial

Other Names:

       

Poison Hemlock (Conium maculatum)

Poison hemlock, also known as hemlock, poison parsley, or spotted parsley, is a dangerous plant to be aware of. It is a biennial herbaceous flowering plant.

Considerations for Pets

  • The entire plant is toxic to animals.
  • Contains the poisonous alkaloid coniine and other alkaloids.
  • Most poisonous during the early stages of growth in the spring, but it is dangerous at all stages of growth.
  • Coniine is concentrated in the seeds, though the entire plant is dangerous to livestock when fresh.
  • Symptoms of poisoning can appear quickly, within 20 minutes to three hours after ingestion.

Considerations for Children

  • The entire plant is toxic to humans.
  • Contains the poisonous alkaloid coniine and other alkaloids.
  • Most poisonous during the early stages of growth in the spring, but it is dangerous at all stages of growth.
  • Has a smooth, purple-spotted, hollow stem.
  • Symptoms of poisoning can appear quickly, within 20 minutes to three hours after ingestion.

Taxonomy and Nomenclature

  • Scientific Name: Conium maculatum
  • Common Names: hemlock, poison hemlock, poison parsley, spotted parsley, deadly hemlock
  • Family: Apiaceae (carrot or parsley family)
  • Genus: Conium

Distribution and Habitat

  • Native to Europe and Asia (Eurasia).
  • Naturalized throughout much of North America after being introduced as an ornamental plant.
  • Common in western Washington on roadsides, in open fields, and in natural areas.
  • Grows throughout the United States.
  • Occurs on borders of pastures and cropland, gradually invading perennial areas.

Ecological Role

  • Considered invasive in some regions.
  • Can quickly infest large areas.
  • Non-native plant that originated in Europe.
  • Identified as a Class-C noxious weed.

Morphological Characteristics

  • Erect biennial herb that can grow 3 to 10 feet tall.
  • Coarse biennial herb with a smooth, purple-spotted, hollow stem.
  • Leaves resemble parsley.
  • First-year plants produce ground-level rosettes.
  • Stems are branched at the top and often mottled with purple spots.
  • Grows 3-8 ft. (0.9-2.4 m) tall.

Quirky Facts

  • In ancient Greece, poison hemlock was used to poison political prisoners.
  • Some birds, such as larks and quails, are not poisoned by hemlock.

Interactions with Other Organisms

  • Often mistaken for water hemlock or wild parsnip.
  • Similar in appearance to other plants with 'hemlock' in their common names.

Further Information

  • www.btny.purdue.edu/weedscience/
  • Department of Animal Science at Cornell University (for information about poisonous plants).
  • Botanical.com, a modern herbal.
  • USDA NRCS PLANTS Database
  • Southern Indiana Cooperative Weed Management Area www.SICWMA.org