Lupinus littoralis aka Seashore Lupine

Lupinus littoralis is also called seashore lupine. It belongs to Fabaceae, the pea family. This plant lives for more than one year. It comes from North America's west coast. Its range starts in southwest British Columbia. It extends south to northwest California. It also grows in western Washington and western Oregon. In the wild, it grows on sandy shores. It is not native to Britain or Ireland. Plants reach about 1.6 feet [0.5 metres] tall and wide.

Plants For A Future gives June through October as bloom time. Each flower has both male and female organs. Bees pollinate the flowers. Seeds ripen from July through October. The plant grows fast and forms root nodules. These small lumps hold soil bacteria that fix nitrogen. This means they take nitrogen from the air. The lupine uses some of it to grow. Nearby plants may gain some of it too.

Grow this species in full sun and soil that drains well. It will not grow in shade. It grows in sand, loam, or clay, even poor soil. Choose acid to neutral soil, not alkaline soil. It likes moist soil. Once plants take root, they can cope with drought. Avoid sites that stay too wet through winter. Plants For A Future lists USDA zones 6–9. It says plants cope with strong winds, but not direct sea exposure. Bear this in mind when choosing a site near the coast.

The plant suits garden beds and serves as green manure. Its fast growth and nitrogen fixation help on poor soils. Take care with its roots; it dislikes root disturbance. You can grow new plants from seed. Soak seeds in warm water for a day first. Sow under glass in early spring, or outdoors in mid-spring. Seeds may take around two weeks to sprout. Mice may harm seeds sown outdoors, so they may need protection. Plants are hard to divide. In spring, you can also take basal cuttings from their base.

The long, tough roots hold starch and taste sweet. They can reach about 3.3 feet [1 metre] long. Records describe roasting and drying the roots for food. Some accounts also note grinding them for later use. Raw roots contain alkaloids that may be poisonous. Do not eat raw roots. These past food uses do not prove they are safe for casual eating. Plants For A Future records no known medicinal uses.