Poison hemlock (Conium maculatum)

Poison Hemlock

Conium maculatum

WARNING! All parts of the plant are DEADLY to people, livestock, and wildlife when ingested.


  • Native to Europe and Asia
  • Grows up to 3m tall with musty smelling fern-like leaves
  • Large clusters of five-petalled white flowers that can produce 40,000 seeds per plant. These seeds are viable for up to 6 years.
  • Mature plants have thick, hollow, hairless stems with purple spots and streaks.
  • Grows in a variety of conditions, but prefers moist soil with sun.

Consequences of invasion

  • WARNING! All parts of the plant are DEADLY to people, livestock, and wildlife when ingested. Young plants can be mistaken for carrots.
  • This plant can outcompete native vegetation, especially in riparian ecosystems.

Status in the CKISS region

  • There are a number of known poison hemlock sites, predominantly in the Creston Invasive Plant Management Area (IPMA). It has also been found in the Nelson and Lower Arrow IPMAs.
  • Because of its limited distribution, the goal is to eradicate this species from these sites and prevent further spread into new areas.
  • Please report any findings of this species immediately.
  • To learn more about how CKISS classifies and manages invasive species, see our Invasive Species Priority Lists page.

Integrated pest management options

  • Mechanical: For small patches, roots may be dug up. Wear full personal protective equipment and wash hands thoroughly after treatment.
  • All landfills within the RDCK and RDKB accept invasive plant species for free. Ensure your material is bagged in clear plastic bags and notify the attendant that you have invasive plant species. Plants must be identifiable through the bag. For more information please see the RDCK Resource Recovery Bylaw.
  • Mechanical: Poison hemlock should not be mowed, as mowing can disperse inhalable toxins into the air.
  • Chemical: Herbicides are available. More information here.
  • Biological: Not currently available.
  • Learn about becoming PlantWise to avoid spreading poison hemlock.

Additional resources