Coastal Bush Lupine (Lupinus arboreus) is a shrub in the Legume family (Fabaceae). Easily recognized by its spires of bright yellow flowers, it also has purple-flowering forms in the wild, although they are less common. The leaves are gray-green and covered with fine, silky hairs. The palmate leaves are made up of 5 to 7 leaflets. Coastal Bush Lupine supports a wide range of pollinators, especially butterflies and moths.

It is native to coastal habitats such as bluffs, dunes, and slopes, where it provides erosion control. Grow in full sun in very well-drained soil in a yard that can accommodate its large size.

Because it has been widely introduced, there is some uncertainty about its native range; it is thought to be native from Point Reyes National Seashore south to San Luis Obispo County. One of the few native plants that the California Invasive Plant Council has determined is invasive in regions outside its natural range. It's invasive in north coast dunes, especially around Humboldt Bay. With its large number of seeds, Coastal Bush Lupine can become an aggressive spreader in some parts of California; cutting off the dead flower stalks before they form seeds can control this issue.