Description:
Poison hemlock is a biennial that grows in moist areas. The stem is hollow, with ridges and purple colored spots. It sometimes grows to 10 feet. Poison hemlock has alternate, lacy, fern-like leaves. The flowers, blooming between May and August, are small and white, and grow in groups looking like umbrellas. Poison Hemlock is one of the most poisonous plants known and the toxicity remains in the plant for up to three years after the plant dies.

• Mechanical: The plant may need to be cut several times, during the growing season, to prevent seed production.
• Biological: A defoliating moth is very effective in reducing seed production.
• Herbicide: Refer to the State Noxious Weed Control Board site