Page authors: Don Knoke, David Giblin
Rumex obtusifolius
bitter dock

Distribution: Occurring on both sides of the Cascades in Washington; Alaska to California, east to the Atlantic Coast.

Habitat: Moist roadsides and wasteland.

Flowers: March-September

Origin: Introduced from Euraisa

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Wind


Robust perennial from a large root, without rhizomes, the single stem unbranched below the inflorescence, 6-12 dm. tall.


Basal leaves with sheathing stipules and long petioles, the blade broadly oblong or ovate-oblong, cordate at the base, 10-20 cm. long; cauline leaves several, reduced upward.


Inflorescence a large panicle, the branches ascending, leafy to mid-length; flowers numerous, borne in verticils, the lower whorls several times as far apart as the upper; pedicels slender, recurved, longer than the perianth, jointed below mid-length; flowers perfect, greenish-brown; outer 3 perianth segments 3 mm. long; inner 3 segments ascending, ovate, 5 mm. long, strongly veined, with 2-4 teeth on each margin, usually one segment with a prominent lump on the base; styles 3.


Achene 2 mm. long, smooth.

Accepted Name:
Rumex obtusifolius L.
Publication: Sp. Pl. 1: 335. 1753.

Synonyms & Misapplications:
Rumex crispatulus Michx.
Rumex rugelii Meisn.
Additional Resources:

PNW Herbaria: Specimen records of Rumex obtusifolius in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Rumex obtusifolius checklist entry.

OregonFlora: Rumex obtusifolius information.

E-Flora BC: Rumex obtusifolius atlas page.

CalPhotos: Rumex obtusifolius photos.

USDA Plants: Rumex obtusifolius information.

32 photographs:
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