Poison hemlock
Conium maculatum
- Plant type
- forb
- Settings
- Riparian and wet ground, Disturbed ground
- Risk
- High risk Our rating from the cited sources.
- Review
- Not yet reviewed by a veterinarian.
Photos
Planned.
How to tell it
Tall plant, 6 to 10 ft; hollow stem with small purple spots; delicate parsley-like leaves; white taproot; ditches and moist waste places (ARS).
Look-alikes: Planned.
What to do on a site walk
- Remove or fence off before move-in.
- Keep pregnant does away.
Why it matters
- Toxic principle
- Piperidine alkaloids (coniine, gamma-coniceine)
- Toxic parts
- All parts
- Basis for our rating
- Chewgrass rating. ARS: can be fatal; causes birth defects in goats exposed early in gestation.
Signs in goats
Trembling, frothing, staggering, dilated pupils, weak pulse, breathing failure; mousy smell on breath and urine (ARS, Merck). Birth defects in kids when does are exposed at days 30 to 60 of gestation (ARS).
If you think an animal has been poisoned, call your vet right away.
Season
Leaves most toxic in spring before flowering; toxic green or dried (ARS).
Sources
- USDA ARS Poisonous Plant Research Lab: Poison Hemlock
- Second source (poisonousplants.ansci.cornell.edu)
Links last checked: 2026-10-31