Lupine

Lupinus polyphyllus (Fabaceae) is an erect herbaceous perennial native to western North America from southern Alaska and British Columbia south through the western states to Utah and California. It grows on stout stems to about 5 feet tall, producing palmately compound leaves with 9 to 17 leaflets (each 3 to 15 cm long). Tall flower spikes are typically blue to purple in wild populations, though cultivated forms span white, yellow, red, pink, orange, and bicolored selections.

Large-leaved lupine thrives in full sun on moist, acidic to neutral soil (pH 4.5 to 7.0) and is found in wetland margins and moist meadows in the wild. As a legume, it fixes atmospheric nitrogen and improves soil fertility. Seeds contain bitter toxic alkaloids in most forms. The Russell hybrid series, derived partly from this species, dominates the ornamental lupine market. It blooms in spring to early summer and can be short-lived as a perennial, especially in heavy or poorly drained soils. Hardy in Zones 5a to 9b.