Broad-leaf lupine is an attractive perennial with erect stems up to 1 meter in height, varying with variety from sparsely haired to heavily haired. The stems typically have 6-8 leaves with the lower leaves having petioles 2-3 times longer than the blade. The lower leaves tend to persist through flowering time. The petioles of the upper leaves range from 1-2 times longer than the blades. The 7-9 leaflets are elliptic to obovate in shape and each ranges from 3-6 cm long and 10-20 mm wide. The upper leaf surface tends to be less haired than the lower surface.
The inflorescence consists of several showy racemes from 10-20 cm long. the thin flower pedicels range from 4-9 mm long. The flowers range from light blue to bluish or lavender, or may be marked with bright violet. The flowers range from 12-15 mm long. The back of the banner lacks hairs and is distinctly well reflexed backwards from the wings and keel (Index = 15-30.) The wings lack hairs and completely cover the curved keel.The calyx is silky to shaggy-haired and lacks a spur or sac. The upper calyx lip is shallowly double-toothed. The seed pods range from 2-3 cm long and average 8 mm wide.
Columbia Gorge Lupine: var. thompsonianus - Plants of low-mid elevation in the eastern Columbia River Gorge. Plants covered with whitish to reddish hairs on the calyx, within the inflorescence, and often on the leaves and stems. The keel is nonciliate. Columbia Gorge broad-leaf lupine is often well over 25 cm tall.
Subalpine Lupine: L. arcticus ssp. subalpinus (formerly var. subalpinus) - Plants of alpine and subalpine ridges and meadows from Alaska south to the Cascade Mts. Plants covered with whitish to reddish hairs on the calyx, within the inflorescence, and often on the leaves and stems. The keel is ciliate and plants tend to range from 10-25 cm in height.
Broadleaf Lupine: L. latifolius ssp. latifolius (formerly var. latifolius) - Plants of open meadows and grasslands or open woods from the coast to open montane slopes, mostly west of the Cascades from southern British Columbia south to the Sierra Nevada of California. Plants covered with straight, appressed hairs all pointing the same direction. Common broad-leaf lupine is usually over 25 cm tall.
Common broad-leaf lupine is generally found on open lowland prairies as well as wooded to open mountain slopes.
Common broad-leaf lupine may generally be found west of the Cascade crest to the Pacific Ocean from British Columbia south to the Sierra Nevada of California.In the Columbia River Gorge, it may be found between the elevations of 100'-4700' from the west end of the Gorge eastward to near the Klickitat River.