Distribution: East of the Cascades in Washington; British Columbia south to Oregon, east to Saskatchewan and Wyoming.
Habitat: Often in deep, fine soils in shady forest, also in cliffs and other rocky sites in open woods and thickets, at moderate to high elevations in the mountains.
Flowers: May-July
Origin: Native
Conservation Status: Not of concern
Soft-hairy or sparsely woolly perennials with creeping or climbing, slender stems; plants scarcely viny in var. dissecta, found in the Wenatchee Mountains of Washington.
Leaves opposite, ternate, firm but not succulent, the leaflets lance-ovate to triangular or sub-orbicular, lobed or unlobed, the margins entire or toothed.
Flowers solitary, terminal on short axillary branches on naked peduncles 5-15 cm. long; sepals usually 4, ovate-lanceolate to elliptic-oblong, acuminate, 3.5-6 cm. long, violet-blue to pale blue; petals none; stamens numerous, the outer ones often sterile; styles 3-6 cm. long, plumose, persistent.
Achenes short-pubescent.
PNW Herbaria: Specimen records of Clematis occidentalis in the Consortium of Pacific Northwest Herbaria database.
WA Flora Checklist: Clematis occidentalis checklist entry.
E-Flora BC: Clematis occidentalis atlas page.
CalPhotos: Clematis occidentalis photos.
USDA Plants: Clematis occidentalis information.