Geranium robertianum
herb-Robert, stinky-Bob

Distribution: Occurring west of the Cascades crest and in the Columbia River Gorge in Washington; Alaska to California, east to Montana, further east in Canada, the Great Lakes region, and eastern North America.

Habitat: Forest understory and forest edges, riparian zones, and other lowland areas with natural or man-made disturbances.

Flowers: March-August

Origin: Introduced from Europe

Growth Duration: Annual, Biennial

Conservation Status: Not of concern


Annual or biennial; stems 1-5 dm, decumbent or ascending, hairy, often reddish.


Leaves 3.5-10 cm broad, palmately divided nearly to base into 5 segments, segments pinnately lobed or dissected, blade round in outline, somewhat hairy.


Inflorescence 2-flowered; flowers radial, on pedicels 5-20 mm; sepals 5, 6-8 mm, ridged lengthwise, covered with soft hairs, bristle-tipped; petals 5, 10-14 mm, light pink to bright purplish pink; fertile stamens 10, anthers generally purple; stylar column 21-24 mm, stigmas 1 mm.


Mericarps 5, 2.5-3 mm, covered with netted ridges, glabrous or hairy; seeds smooth.

Accepted Name:
Geranium robertianum L.
Publication: Sp. Pl. 2: 681-682. 1753.

Synonyms & Misapplications:
(none provided)
Additional Resources:

PNW Herbaria: Specimen records of Geranium robertianum in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Geranium robertianum checklist entry.

E-Flora BC: Geranium robertianum atlas page.

CalPhotos: Geranium robertianum photos.

USDA Plants: Geranium robertianum information.

36 photographs:
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