Spiny Ceanothus Plant Care

Spiny Ceanothus (Ceanothus spinosus) belongs to the Rhamnaceae family within the Ceanothus genus. Spiny Ceanothus is native to southern California and northern Baja California. Spiny Ceanothus is also known as Buckbrush.

Spiny Ceanothus displays an upright, spreading shrub growth habit, reaching up to 10 ft tall with a spread of approximately 10 ft. Spiny Ceanothus produces clusters of small blue, white, or pink flowers.

Leaf size: approximately 2 inches.

Water a young or newly planted Spiny Ceanothus every 7–14 days, soaking the whole root zone, until it is established — usually one to two growing seasons. Established trees mainly need water during long dry spells. In a container, water whenever the top few centimetres of soil are dry.

Spiny Ceanothus thrives in full sun to partial shade.

Ceanothus spinosus tolerates temperatures of 50–90°F. Spiny Ceanothus prefers humidity levels of 40–70%.

Well-draining sandy loam with added compost for moisture retention. Good drainage is essential for Spiny Ceanothus to prevent waterlogging, which leads to root rot and fungal issues.

Feed Spiny Ceanothus every 8 months during the growing season with a balanced, slow-release fertilizer at the rate on the label. Established trees in good soil often need little extra feeding, so let weak growth or pale foliage guide you.

Stop feeding by late summer so new growth can harden before winter.

The PlantoScan app can remind you when to water and when to fertilize each plant.

Choose a spot with full sun to partial shade and well-draining sandy loam with added compost for moisture retention. Avoid low spots where water collects after rain.

Spiny Ceanothus is suited to USDA Zone 12a.

Plant container-grown or balled-and-burlapped trees in spring or early autumn, setting the root flare at soil level, and water well after planting.

Spiny Ceanothus can spread to about 10 ft (3 m) and reach about 10 ft (3 m) tall. Space plants about 10 ft (3 m) apart so mature crowns don't crowd each other, and plant at least half that distance from buildings, fences and paths.

Planning a row or hedge? Try the tree spacing calculator.

Prune Spiny Ceanothus while it is dormant in late winter: first remove dead, damaged and crossing branches, then thin lightly for shape.

If it flowers in spring, prune right after flowering instead so you don't remove next year's buds. Never take off more than about a quarter of the tree in one year.

Spiny Ceanothus is frost-tender (hardy to USDA zone 12). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.

Spiny Ceanothus can be propagated through softwood cuttings, semi-hardwood cuttings, layering. Similar propagation techniques also apply to blueblossom plant care, which shares the same genus.

See all plants toxic to cats and plants toxic to dogs.

Spiny Ceanothus is susceptible to aphids, scale insects, spider mites. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.

Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.

Spiny Ceanothus grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Spiny Ceanothus is native to southern California and northern Baja California. In cooler regions, grow Spiny Ceanothus as a houseplant or bring it indoors before the first frost.