Page authors: Don Knoke, David Giblin
Conium maculatum
poison hemlock

Distribution: Occurring on both sides of the Cascades crest in Washington; widely distributed throughout North America.

Habitat: Roadsides, fields, wastelots, and other disturbed open areas, often where soil is moist.

Flowers: April-August

Origin: Introduced; native to Europe

Conservation Status: Not of concern


Coarse, freely-branched biennials from a stout taproot, 0.5-3 m. tall, with purple-spotted, hollow stem.


Leaves large, all cauline, ternate-pinnately dissected, the ultimate segments small.


Compound umbels numerous, the rays sub-equal, 1-4 cm. long; involucre and involucel of several small, lanceolate bracts or bractlets; calyx teeth obsolete; petals 5, white.


Stylopodium depressed-conic; fruit glabrous, broadly ovoid, 2-2.5 mm. long, with prominent, raised, wavy, almost-winged ribs.

Accepted Name:
Conium maculatum L.
Publication: Sp. Pl. 1: 243. 1753.

Synonyms & Misapplications:
(none provided)
Additional Resources:

PNW Herbaria: Specimen records of Conium maculatum in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Conium maculatum checklist entry.

E-Flora BC: Conium maculatum atlas page.

CalPhotos: Conium maculatum photos.

USDA Plants: Conium maculatum information.

25 photographs:
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