Ceanothus maritimus aka Maritime Ceanothus

Ceanothus maritimus, or maritime ceanothus, is an evergreen shrub in the buckthorn family, Rhamnaceae. Its native range lies in northern San Luis Obispo County, California. It grows on coastal bluffs within that small native range. Kew lists its life form as a shrub or subshrub. It is not native to Britain or Ireland.

The plant reaches about 3.3 feet [1 metre] in height. Its evergreen habit keeps foliage present through the year. Its low form suits use as ground cover in coastal gardens. Plants For A Future also lists it for woodland gardens. The supplied species accounts give no clear spread measurement. They also provide no detailed account of its bark or leaves. Flowers appear from April to May. Each flower has both male and female organs. The plant can fix nitrogen.

Choose a warm, sunny site with soil that drains well. It also accepts light shade, including open woodland shade. Sandy and loamy soils suit it. Soil may be mildly acid, neutral, or mildly alkaline. It tolerates some lime, but shallow chalk does not suit it. It can grow in either dry or moist soil. Plants For A Future reports cold tolerance to about 23°F [−5°C]. That source places outdoor British cultivation in milder districts. It also lists USDA zones 7–10, a broader hardiness guide.

Plant young specimens straight into their lasting garden position. Their roots do not respond well to disturbance. Avoid hard pruning, which this species dislikes. Keep cuts to stems no thicker than a pencil. Carry out any needed pruning in spring. Seed offers one means of propagation. Fresh seed can go into a cold frame after ripening. Stored seed needs treatment before sowing, including soaking and chilling. The evidence provides no species-level account of pests or diseases.

Beyond ground cover, this shrub has several reported uses. Its flowers yield a green dye. Its parts contain saponins that make lather when crushed in water. Flowers and young seed cases provide material for this soap. It removes dirt better than oils. Plants For A Future records no known food or medicinal uses. It also reports no known hazards. That statement does not establish that eating the plant is safe.