Lupinus succulentus

Common Names

Arroyo Lupine, Hollowleaf Annual Lupine, Succulent Lupine, Bigleaf Lupine

Summary

Arroyo lupine, also known as hollowleaf annual lupine, is a native annual herb in the Fabaceae that grows 2–4 ft tall with fleshy, branched stems and palmately compound leaves of 7–9 leaflets. It bears spikes of sweetly fragrant purple-blue pea-shaped flowers with a white patch on the banner, blooming from late winter to spring, and fixes nitrogen in the soil. It tolerates heavier soils like clay and readily reseeds, often colonizing open or disturbed areas such as roadsides; native to California with distribution into adjacent Arizona and Baja California, it is commonly used in native plantings and wildflower gardens.

For cultivation, it grows best in full sun on well-drained soil, is hardy in USDA zones 7–10 and frost-sensitive, and becomes drought-tolerant after establishment. Keep soil slightly moist until established, then weekly watering is sufficient, with more during hot periods; avoid overwatering. It is propagated by seed, sowing directly when soil temperatures reach 55–70°F, with germination typically 15–75 days; scarification or nicking and soaking the seeds overnight improves germination. It readily self-seeds and is used for ornamental borders, native/wildlife gardens, erosion control, and bank stabilization; all parts are toxic if eaten.

Lifecycle

Annual, can appear perennial in NW, sometimes persisting more than one season, described as annual/biennial

Height

1-4 feet

Spread

1-3 feet

Hardiness Zones

Zones 7-10

Sunlight Requirements

Ideally full sun; tolerates partial sun and partial shade.

Soil Type

Moist clay or heavy soils

Soil Drainage

Well-drained soil

Soil pH

6.1-7.8 (slightly acidic to slightly alkaline)

Bloom Color

blue, blue-purple, purple, white, pink, lavender

Bloom Time

Spring to Summer

Foliage Color

Green

Fall Foliage Color

Green

Leaf Lifecycle

Deciduous

Growth Rate

Fast

Seasons of Interest

Spring, Winter, Summer

Propagation Methods

Seed propagation; no vegetative propagation reported.

Attracts Wildlife

Attracts bees, butterflies, other pollinators, birds