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Pesticide Safety Education Program

Ohio State University Extension

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Poison hemlock (Conium maculatum)

Description: A herb in the carrot family that grows 3 to 8 feet tall.

Life cycle: Biennial

Habitat: Grows in dry to most soils and is often found near roadsides. Field borders, hiking trails, railroad tracks, stream banks, irrigation ditches, waste areas, riparian woodlands and open floodplains of rivers and streams.

Flower: Flowers are small, white, and borne in umbrella-shaped cluster about 3 inches across.

Fruit: Ridged and flattened seeds.

Leaf: Leaves are shiny green.

Stem: Stems are stout, hollow, ridged and purple spotted.

Root: Thick, white taproot

The problem is….all plant parts are poisonous; however, the seeds contain the highest concentration of poison. It contains highly poisonous alkaloids toxic to all classes of livestock and humans. It may act as a pioneer species quickly colonizing disturbed sites and displacing natives.

Young poison hemlock, 9527.

Poison hemlock, 1312.

Poison hemlock leaf, 8917.

Poison hemlock stem, 8588.

Poison hemlock hollow stem, 8910.

Poison hemlock flowers, 8933.

Poison hemlock large patch, 9141.