Stems and leaves of lupinus odoratus
are usually hairless at the flowering stage, though young plants generally have a sparse hair covering. The bright, yellowish-green leaves are basal, arranged in a rosette with the stalks (up to 5 inches long) angled outwards, close to the ground. Leaflets are comparatively broad, with the widest point quite near the tip.
Flowers are dark pink to violet, around a third of an inch long, produced in an elongated cluster along the upper half (up to 6 inches) of a leafless stalk. The center of the banner petal is white or pale yellow, becoming purple when mature. The calyces may have a few hairs on the tips but are otherwise hairless; they are divided into a rounded or shallowly toothed upper lip and a slightly longer lower lip. Fruits are broad, flattened, oblong pods up to 1 inch in length, with long hairs along the margins.