Page authors: Don Knoke, David Giblin
Heracleum maximum
American cow-parsnip, American hogweed
WTU specimens
Other herbaria
WTU images

Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east across North America except in the southeastern U.S.

Habitat: Moist areas, including meadows and forest edge from low to middle elevations.

Flowers: June-August

Origin: Native

Conservation Status: Not of concern


Robust, single-stemmed perennial from a taproot or a cluster of fibrous roots, 1-3 m. tall.


Leaves large, once ternate, with broad, petiolate, coarsely-toothed and palmately-lobed leaflets 1-3 dm. long and wide, the lateral ones narrower than the central, thinly woolly on the lower surface; petioles sheathing and expanded.


Inflorescence of compound umbels on terminal and axillary peduncles, the terminal umbel 1-2 dm. wide; rays mostly 15-30, up to 10 cm. long; involucre of 5-10 deciduous, narrow bracts, 0.5-2 cm. long; involucel of similar bractlets; pedicels 8-20 mm. long; calyx teeth obsolete, flowers white.


Fruit obovate, 7-12 mm. long and 5-9 mm. wide, strongly flattened dorsally, nearly glabrous, the dorsal ribs narrow, the lateral ones broadly winged.