Ceanothus purpureus aka Hollyleaf Ceanothus

Ceanothus purpureus is an evergreen shrub known as hollyleaf ceanothus. It belongs to the buckthorn family, Rhamnaceae. Its native range lies in California's Vaca Mountains. Kew places it in a subtropical climate. In the wild, it grows on dry, rocky hills. These sites lie below about 1,800 feet [550 metres]. It is not native to Britain or Ireland.

The shrub reaches about 6.6 feet [2 metres] in height. Its evergreen habit gives it a place in year-round planting. Spreading forms can cover the ground on warm, sunny slopes. It also suits the sunny edge of a woodland garden. The evidence gives no mature width for the species. Flowers appear from April to June on the previous year's growth. Each flower has both male and female organs. Bees pollinate the flowers, and the plant can fix nitrogen. Ripe capsules throw out their seeds with force.

Choose a warm site with sun and soil that drains well. The plant also accepts light shade. Sandy and loamy soils suit it. It grows in mildly acid, neutral, or mildly alkaline conditions. It tolerates some lime but does not thrive on shallow chalk. Soil may be dry or moist, provided drainage remains good. Plants For A Future lists USDA zones 7–10. It also notes that plants lack full hardiness at Kew. Outdoor plants fare better south and west of London.

Set young plants in their final site while still small. They dislike disturbance around their roots. Avoid heavy pruning, as repeated size control can shorten their lives. When pruning is needed, do it just after flowering. Keep cuts to stems no thicker than a pencil. These limits matter when choosing a site with enough room. Fresh seed can be sown in a cold frame. Stored seed needs pretreatment before sowing.

The flowers yield a green dye. Saponins in the plant form lather when crushed with water. Flowers and young seed cases provide useful soap material. This soap cleans dirt but removes oils less well. Plants For A Future records no known food or medicinal uses. It also reports no known hazards, rather than proof of safety. The supplied evidence names no specific pests or diseases.