This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Native. Perennial. Propagates by seeds.
Time of bloom: July to August.
Seed-time: August to September.
Range: Nebraska and the Dakotas to the plains of the Columbia
River, southward to New Mexico and Arizona. Habitat: Prairies, hillside slopes; wild pastures and meadows.
On the sides of the vast foothills of the Rocky Mountains this and other species of Lupines often completely cover the ground for miles, and when in bloom the wide tracts of blue flowers are visible at a great distance. If the plant is to be used for hay it should be harvested while in bloom, or else very late, after the seeds have ripened and been cast from the pods. The leaves remain succulent until frost.
This is a very variable species but is usually a somewhat shrubby, bushy-branched plant, one to nearly three feet in height, densely covered with fine, silky, appressed hairs. Leaves on slender petioles about as long as the blades, the leaflets five to eight, nearly smooth above but silvery-hairy beneath, linear to lance-shaped and pointed at both ends. Racemes terminal, usually densely flowered, two to five inches long; calyx-lips unequal, the upper one rather broad, two-toothed, the lower one longer and entire; petals usually purple but sometimes pale blue or cream-colored, the standard and keel sometimes finely hairy. Pods about an inch long, silky-haired, three- to five-seeded.
Means of control should be similar to that of the Nebraska Lupine.