Ceanothus (California lilac)

Ceanothus (California lilac) is a genus of shrubs or small trees in the buckthorn family Rhamnaceae, comprising 50 - 60 species. This genus is confined to North America, with the centre of distribution in California, thus the common name California Lilac.

Ceanothus are mostly evergreen, with a few species which can adapted to cold winters are deciduous. The ovate-shaped leaves of Ceanothus have unique vein structure. There are three very prominent parallel veins extending from the leaf base to the outer margins of the leaf tips. The leaves have a shiny upper surface that feels 'gummy' when pinched between the thumb and forefinger. The roots of most species have red inner root bark. The leaves are a good source of protein and the stems and leaves have been found to contain a high amount of calcium. The plant is a good source of nutrition for deer, especially mule deer on the west coast. Porcupines and quail have been seen eating stems and seeds of the plant. Ceanothus species are used as food plants by the larvae of some Lepidoptera species including the bucculatricid leaf-miners, which feed exclusively on the genus.

The species are grown for their tiny, beautiful flowers, which are borne in large clusters in late spring or in late summer to early autumn. The tiny flowers are reported to be intensely fragrant to the point of being nauseating, and come in white, greenish-white, blue, pale purple or pink, maturing into a dry, three-lobed seed capsule. The seeds can be lie dormant for hundreds of years. Ceanothus species are typically dependent on forest fires to trigger germination of its seeds.

Ceanothus arboreus is a drought-tolerant shrub endemic to California, especially to the Channel Islands. It is commonly known as Feltleaf Ceanothus. It can also known as California Lilac, California mountain lilac or island mountain lilac. It is a spreading shrub growing up to 6 m tall, has glossy dark green leaves which are leathery or felt-like on the undersides. Ceanothus arboreus is a fast-growing ornamental plant, grown for its showy, tiny, bright blue flowers borne on large clusters. Some varieties and cultivars have light, powder blue blooms, and others bear darker blue flowers. Its fruits are three-lobed, triangular capsules.

Ceanothus incanus (Coast whitethorn) is a species of shrub endemic to California, where it is known from the San Francisco Bay Area through the north Coast Ranges into the Klamath Mountains. This thorny species can grow to 4 meters high with the woody parts grey in color and waxy and somewhat hairy in texture. The evergreen leaves are grey-green in color, alternately arranged, oval-shaped and usually smooth along the edges. The flowers comes in beautiful clusters of white in spring. the fruit is a rough, lobed capsule containing three seeds.

Ceanothus grows well in full sun and well-drained soil, and it makes perfect wall shrub. Propagation is by seed in autumn; greenwood cuttings (deciduous) or semi-ripe cuttings (evergreen) in autumn. Ceanothus is usually hardy but beware of honey fungus attack.

Ceanothus americanus
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