Poison Hemlock

is extremely toxic to anything that consumes it. Hemlock poisoning causes paralysis, convulsions, and eventual death. It is important for growers to notice and remove any hemlock from their hay or pasture fields, including ditch banks, fence rows, and other idle areas.
reproduces solely by seed. Seeds germinate in autumn and plants develop rapidly throughout the winter and spring.
can be distinguished by the purple spots on the stem. It is commonly confused with wild carrot, cow parsnip, and parsley. Human deaths have occurred from harvesting and consuming this plant.

To prevent seeds from spreading, it is important to minimize soil disturbance. Eradicate new and/or small infestations immediately by hoeing, pulling, or mowing before or at early flower stage. It is important to implement proper seeding, grazing, fertilization, and irrigation management to promote the growth of desired species.
In cropland, plowing or repeated cultivation will prevent poison hemlock establishment. In other areas, repeated mowing can be used to remove bolting plant material, reduce its competitive ability, and prevent seed production.
Herbicide can be applied any time after the sprouts have emerged. Herbicides such as 2,4-D (amine and ester formulations), MCPA, and Escort are effective. Approved aquatic formulations are available to control plants near water. Treating this weed with herbicide may require repeated applications to deplete the seed bank. The length between applications depends on the herbicide. Always read and follow the label when using any herbicide.