Showy, elongate clusters of purple, pea-like flowers top the 1-2 ft. stems of this perennial lupine. Blue, pea-like flowers are in an upright, elongated, terminal cluster on an erect stem with palmately compound leaves. Its leaves are palmately divided into 7-11 leaflets. Occasionally flowers range from pink to white.

The plant was once thought to deplete or "wolf" the mineral content of the soil; hence the genus name derived from the Latin lupus ("wolf"). Actually the plant and all the family enhances soil fertility by fixing atmospheric nitrogen into a useful form. In the south this flower has narrower leaflets and is often recognized as a separate species, Nuttal's Lupine (L. nuttallii). Two southern species with undivided elliptic leaves are Spreading Lupine (L. diffusus), with blue flowers and a whitish spot on the standard (upper petal), and Hairy Lupine (L. villosus), a hairy plant with lavender-blue flowers and a red-purple spot on the standard. They are found from North Carolina to Florida and west to Louisiana. A species found in Nebraska, Wyoming, and Colorado, Nebraska Lupine (L. plattensis), has blue flowers with a dark spot on the standard and paddle-shaped leaflets. L. polyphyllus is becoming extremely abundant in the Northeast, particularly Maine and adjacent Canada; it was introduced from the Northwest.