Also Known As
Big-leaf lupine is a perennial forb with purple to blue flowers, distinguished from the other 200 lupine species in North America by hairless or sparsely hairy banner and keel.
Big-leaf lupine is a perennial forb with purple to blue flowers, distinguished from the other 200 lupine species in North America by hairless or sparsely hairy banner and keel. The leaves are palmately compound with 9-17 leaflets (but sometimes as few as 5).
Did You Know?
The genus name, Lupinus, comes from the Latin word for wolf, since it was believed that lupines 'wolfed' nutrients from the soil, preventing other plants from growing near it. In fact, lupines are able to fix nitrogen from the atmosphere, so that they are able to thrive in nutrient-poor soils where few other plants survive.
Flowers form a spike of up to 80 purple to blue, asymmetrical flowers. There can be one to several spikes per plant, and each spike can reach 8 to 16 in (20 to 40 cm). Each flower has five petals, is ½ to ¾ in long (1.5 to 2 cm) with a small yellow or white patch that turns red-purple with age. Some ornamentals may have pink or magenta petals. Flowers are typical of those in the Pea family, with a butterfly like corolla. There is a banner petal at the top, with two lateral wing petals, and two petals fused into a keel are set between the wing petals. In the center, there are 10 stamens, 5 with short filaments and long anthers, and 5 with long filaments and short anthers. Flowers bloom from May to August.
The fruit is a dry hairy capsule (shaped like a pea pod) that turns dark brown and splits when it matures. The fruits are usually clustered towards the tip of the stem, 1 to 2 in (2 to 4 cm) long. Pods open explosively when ripe, and seeds are spread a short distance.
Open sunny places on sandy loamy soil. In California plants generally occur below 7500 ft (2286 m) in moist sites. Prefers sun to partial shade in moist, cool soils. Native to Alaska, Colorado, Idaho, Montana, Nevada, Oregon, Washington, California and Wyoming, Big-leaf lupine was introduced in the Midwest and escaped cultivation.