Lupinus is a genus of flowering plants in legume family of Fabaceae, comprising about 200-600 species. The species can be found in South America, western North America, in the Mediterranean region and Africa. It is commonly known as Lupin.
Lupinus contains mostly herbaceous perennial plants, 0.3 - 1.5 m but some are annual plants and a few are shrubs of up to 3m tall. Lupinus has a characteristic and easily recognized leaf shape, with soft green to grey-green leaves. Some species have leaves with densely silvery hairs. The leaf blades are usually palmately divided into 5-28 leaflets or reduced to a single leaflet in a few species of the southeastern United States. The pea-like flowers (1-2 cm long) are produced in dense or open whorls on a tall, erect spikes. The fruit is a pod containing several seeds. The yellow legume seeds of lupins , called lupin beans, were popular with the Romans. Lupin beans are commonly sold in a salty solution in jars and can be eaten with or without the skin. Lupinus are also cultivated as forage and grain legumes.
Lupinus albifrons (Silver lupine, White-leaf bush lupine, Evergreen Lupine), 1.5 x 0.5 m high and across, is a perennial shrub with leaves that are silver with a feathery texture. It is native to California and Oregon. This species bears light blue to violet flowers on 7 - 30 cm stalks. It is suitable as an ornamental plant in the gardens and also for landscaping. Lupinus albifrons, Lupinus formosus and Lupinus variicolor are food plants for larvae of the endangered Mission Blue butterfly. The butterfly becomes toxic itself when it feeds on the plant, leaving it with a bitter taste to deter predators.
Lupinus polyphyllus (Large-leaved Lupine, Big-Leaved Lupine, Garden Lupine) is native to western North America, from southern Alaska, and British Columbia west to Alberta and western Wyoming, and south to Utah and California. It is commonly grown along streams and creeks where the habitats are moist. It has leaves that are palmately compound with 5-17 leaflets, and flowering stems of up to 1.5 m tall. The flowers (1-1.5 cm long) of blue to purple color are borne on a tall spike. This species is commonly used in garden for its showy flowers. Cultivars with different flower color, including red, pink, white, blue, and multicolored with different colors on different petals have been selected for growing. Hydrids between L. polyphyllus and L. arberous are used and sold under the name Rainbow Lupin, usually hardy and can easily become invasive. The Russel Hybrids grow to about 1 meter tall and have bicolored flowers in blue and white, cream-white and white, and pink and white.
Lupinus grows well in full sun or partial shade, in well-drained, neutral to acidic soil. Propagation is by by seed in spring, basal cuttings in mid-spring. Pests and diseases are aphids, slugs and snails, and mildew.