The Mission of the Yellowstone County Weed Department is to assist the public, private, and other government agencies to manage and control existing noxious weed infestations as well as to prevent new invasive species from infesting Yellowstone County.

Poison HemlockConium maculatum L.

Parsley family - Apiaceae

Photo from Weeds of the West, revised edition

Attribute	Information
Growth Habit	Biennial, erect to 10 feet tall.
Leaves	Shiny green, fern-like, finely divided 3 & 4 times. Lower leaves have long stalks clasping the stem. Upper leaves on short stalks. Musty odor.
Stem	Stout, branched, purple-spotted with distinct ridges.
Flower	Numerous umbrella shaped clusters of tiny white flowers without sepals. Clusters supported by stalks whorled at branch terminals.
Roots	Large white taproot.
Seeds	Paired, 1/8th inch long, ribbed, concave, light brown.
Reproduction	Seeds only.
Habitat	Dense stands along stream and ditch banks, field margins, transportation rights-of-way, pastures, meadows and waste places.
Biological Controls	Hemlock moth (Agonopterix alstroemeriana).
Herbicides	Escort and E2.
Caution	All plant parts are poisonous when eaten by livestock or humans.