Be Weed Aware: Poison hemlock, Poisonous to Humans, Livestock and Wildlife

Poison hemlock contains toxic compounds that make the entire plant poisonous to humans and livestock.  Leaves, stems, seeds and roots all contain the toxic alkaloids making them poisonous.  Toxic levels increase with plant maturity. 

 Poisonings most commonly impact cattle, goats and horses.  Nervousness, trembling and excessive salivation are noticeable symptoms exhibited by livestock that have recently eaten poison hemlock.  Forage prepared as haylage or hay and containing Poison hemlock does little to reduce the plants toxicity.

 Poison hemlock grows 3-8 feet tall and may be found along field edges, urban alleys and areas where construction material has been disposed.  The foliage is lacey in appearance and may be confused with carrot foliage.  Other plants that may be confused with Poison hemlock include: Wild Carrot, Chervil (Bur & Wild) and edibles, parsley and parsnip.

 The stout hollow stems with purple streaks or blotches is a key identifying feature of Poison hemlock.  Tall dead stems from the previous year’s growth may also help in identifying the noxious weed. 

 The small white flowers clusters are observed later in the spring or early summer season.  Confirm the identity of Poison hemlock by sharing a photo of the plant with the Weed Board.  Handle plants with gloves!