Poison larkspur is an attractive perennial wildflower with one to several stout and erect stems arising as much as 70-150 cm high. The stems are hollow and unbranched below the inflorescence. The herbage ranges from slightly hairy to smooth. There are numerous leaves on the stems and these become reduced in size upwards on the stem. The lower leaves range from 10-20 cm wide and are 3-lobed nearly to their base (See photo at right.). Each of the lobes are in turn further divided deeply into 2-3 segments.
The inflorescence is a simple to branched raceme of loosely arranged flowers. The inflorescence often is covered with fine, spreading, yellowish and often glandular hairs. The inflorescence is also noticeably leafy-bracteate below. The pedicels usually are longer than the calyx spur and somewhat spreading and ascending. The sepals are deep blue, each being oblong-lanceolate in shape with pointed tips. They measure 18-25 mm long. The spur is straight and occasionally somewhat arched downwards at the tip. The upper petals are whitish while the lower petals are bluish.
Poison larkspur may be found in moist shady woods and along shaded streambanks.
Poison larkspur is found from the Columbia River Gorge of Washington and Oregon south along the west side of the Cascade Mts. to Humboldt County, California.
In the Columbia River Gorge it may be found between the elevations of 100'-2000' between the Sandy River and McCord Creek.