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Plant Profile: Tree lupine (Lupinus arboreus)

Tree Lupine is a evergreen shrub growing 5-7’ tall and endemic to coastal bluffs, and open woods in central California but has become an invasive species in Southern California and coastal Pacific Northwest. It is a member of the pea family, Fabaceae, that also includes beans, Baptisia, and mimosa. The green to gray-green leaves are palmately compound and have five to twelve leaflets .75-2.5 inches long. The fragrant bright yellow flowers, occasionally blue or purple, are carried in racemes from spring into summer and are attractive to bumblebees, butterflies, moths, hummingbirds, and other pollinators. Seeds are attractive to birds and foliage serves as food for larvae of various butterflies. Like other members of the pea family, tree lupine is nitrogen-fixing and can change the composition of the soil which aids exotics at the expense of native species that are adapted to low nitrogen levels. Tolerates wind, salt, heat, drought, low fertility and fire but not shade or waterlogged soil. Flowers are good for the vase.

Type: Flowering shrub

Outstanding Feature: Flowers

Form: Rounded leafy crown

Growth Rate: Rapid

Bloom: Fragrant bright yellow flowers occasionally ,blue or purple, in spikes from spring into summer

Size: 7-7’ H x 5-7’ W

Light: Full sun, dappled shade

Soil: Fertile, medium moist, well-drained

Hardiness: Zones 8-9

Care: Low maintenance

Pests and Diseases: Slugs, snails, aphids, powdery mildew

Propagation: Seed (presoak 24 hours in warm water); basal cuttings in summer