Ceanothus thyrsiflorus, known as blueblossom or blue blossom ceanothus, is an evergreen shrub in the buckthorn family Rhamnaceae that is native to Oregon and California in the western United States and the state of Baja California in northwestern Mexico. The terms 'Californian lilac' and 'Mountain lilac' are also applied to this and other varieties of ceanothus, though it is not closely related to Syringa, the true lilac.
Two varieties are accepted: Ceanothus thyrsiflorus var. obispoensis Ceanothus thyrsiflorus var. thyrsiflorus
Description Ceanothus thyrsiflorus can grow more than tall and broad in its native chaparral habitat, with glossy green leaves. The clusters of tiny flowers, borne in spring, vary from different shades of blue to close to white. The evergreen leaves are shiny and about long.
Etymology The Latin genus name Ceanothus is derived from the Ancient Greek () 'a spiny plant'. The name was originally used by Theophrastus for another plant, and Linnaeus reused it for Ceanothus.Gledhill, David (2008). "The Names of Plants". Cambridge University Press. (hardback), (paperback). pp 96, 168, 379
Ecology It is popular with birds, butterflies, and other pollinators. It is often visited by honeybees for its pollen.
Cultivation Ceanothus thyrsiflorus has been used in gardens extensively. It prefers a warm, sheltered position in full sun. Several cultivars have been selected, including: 'Blue Mound' which can grow to tall 'Cascade' which may reach of height 'El Dorado', a variegated cultivar with gold edge foliage and powder blue flowersBotanica. The Illustrated AZ of over 10000 garden plants and how to cultivate them, p. 202 Könemann, 2004. 'Repens' which stays as a shrub around tall 'Repens Victoria', forming a sturdy evergreen mound and most useful groundcover with powder blue flowers 'Skylark', a tall type with blue flowers (this cultivar has gained the Royal Horticultural Society's Award of Garden Merit) 'Snow Flurry', with white flowers
References
External links
CalFlora Database: Ceanothus thyrsiflorus (blueblossom) Jepson eFlora (TJM2): Ceanothus thyrsiflorus Ceanothus thyrsiflorus — U.C. Photo gallery