Got Nature? Blog

Photo credit: Pedro Tenorio-Lezama, Bugwood.org

Made infamous through the trial of Socrates, Shakespeare’s Hamlet and Macbeth, and several other works of classic literature, poison hemlock is an extremely toxic plant that will pose a risk this summer and should be handled with caution.

Poison hemlock is a biennial plant, meaning that it has a two year lifespan. Last summer, it went through vegetative growth and largely stayed out of sight. This summer, it will produce small white clusters of flowers and will be more likely to catch the attention of animals and people. Poison hemlock is a member of the parsley family and can sometimes be confused with wild carrot. However, its distinguishing feature is its hairless hollow stalks with purple blotches. If you see these, be careful!

The biggest risk with poison hemlock is ingestion. Lethal doses are fairly small, so it is important for animal owners or parents of young children to identify it in their area and remove it if possible. The toxins can also be absorbed through the skin and lungs, so be sure to wear gloves and a mask when handling these plants.

Symptoms of hemlock poisoning include dilation of the pupils, weakening or slowing pulse, blue coloration around the mouth and eventually paralysis of the central nervous system and muscles leading to death. Quick treatment can reverse the effects, so act quickly.

Resources
Invasive Plant Species Fact Sheets: Poison Hemlock, The Education Store, Purdue Extension Resource Center
Poison Hemlock (Conium maculatum), United States Department of Agriculture (USDA)

Purdue Extension