Page authors: Don Knoke, David Giblin
Delphinium trolliifolium
cow-poison, poison larkspur

Distribution: Occurring west of the Cascades crest and in the Columbia River Gorge in Washington; Washington south to California.

Habitat: Moist, shady woods at low to middle elevations.

Flowers: April-May

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern


Stout perennial from short, thick rhizomes, the several erect stems 7-15 dm. tall, simple below the inflorescence, hollow, glabrous to sparsely hairy.


Leaves numerous, evenly spaced and gradually reduced upward, the blades of the lower ones 10-20 cm. broad, tri-lobed nearly to the base, the 2 lateral lobes deeply divided into 2-3 segments, the segments broadly wedge-shaped and 2-3 times deeply toothed.


Inflorescence elongate and loose, the raceme usually simple, pubescent with spreading, yellowish hairs, leafy-bracteate below; pedicels considerably exceeding the sepal spur, spreading; sepals 5, deep blue, oblong-lanceolate and pointed, 18-25 mm. long, the spur straight, about equal to the blade of the upper sepal; petals 4, small, the lower pair colored as the sepals, the upper pair white; stamens numerous; pistils 3.


Follicles glabrous, about 15 mm. long.

Accepted Name:
Delphinium trolliifolium A. Gray
Publication: Proc. Amer. Acad. Arts. 8: 375. 1872.

Synonyms & Misapplications:
(none provided)
Additional Resources:

PNW Herbaria: Specimen records of Delphinium trolliifolium in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Delphinium trolliifolium checklist entry.

E-Flora BC: Delphinium trolliifolium atlas page.

CalPhotos: Delphinium trolliifolium photos.

USDA Plants: Delphinium trolliifolium information.

24 photographs:
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