An evergreen shrub 11⁄2 to 4 ft high, usually more in width, but often procumbent or semi-prostrate; shoots downy, slender. Leaves one-veined, or somewhat three-veined from the base, alternate, oval, ovate, or broadly oblong, tapered to both ends, 1⁄4 to 3⁄4 in long, the apex rounded or blunt, margins usually wavy, recurved and minutely toothed; teeth gland-tipped; dark green above, rather glaucous, downy or glabrous beneath but usually downy on the midrib and veins only; leaf-stalk very short. Often the principal leaves develop condensed spurs in their axils, bearing clusters of smaller leaves. Flowers closely set in globose, terminal clusters, 1⁄3 to 1⁄2 in. wide, main-stalk 1⁄5 to 3⁄5 in. long (more rarely the clusters are grouped into a compound inflorescence up to 4 in. long); sepals and petals dark blue; filaments blue, anthers yellow. Bot. Mag., t. 9540.
Native of California and a very pleasing shrub, usually compact and spreading, but according to Jepson, the Californian botanist, it may be found slender, erect, and 16 ft high in Mendocino county. It is a success at Kew both in the Rock Garden and against a wall. Blooms in May.
var. vineatus McMinn – A creeping or low, spreading shrub with rather larger leaves than in the type, found in various localities in Sonoma and Mendocino counties.
C. austromontanus Abrams – This species is now united with C. foliosus by leading authorities on the Californian flora. It was described from plants growing in the Cuyamaca Range in San Diego county, south of the main area of distribution of C. foliosus, and differs horticulturally in its low, spreading habit; leaves glossy and wavy-edged; flowers bright blue in small dense clusters. It seems, however, to be very near C. foliosus var. vineatus.
C. 'Edinburgh'. – This ceanothus originated in the Edinburgh Botanic Garden around 1934 among seedlings of C. austromontanus and was distributed under that name. It is clearly a hybrid, with C. griseus (C. thyrsiflorus var. griseus) as one parent (E. Kemp in Gard. Chron., 24th June 1961). Also known as “Edinensis”.
C. 'Italian Skies'. – This ceanothus was raised by E. B. Anderson from seed of C. foliosus received from the University of Washington Arboretum, Seattle, U.S.A., in 1956. It makes a spreading bush with flowers of a brilliant blue arranged in dense, conical trusses 2 to 3 in. long. It appears to agree well with the seed parent in its botanical characters but the species of Ceanothus cross so readily in cultivation that it is perhaps preferable to treat this plant as an independent clone until its identity has been verified. It differs markedly from the form figured in the Botanical Magazine in having compound inflorescences, but this feature is accepted by McMinn as part of the normal variation of the species. Lord Morton has a fine specimen of 'Italian Skies' in his garden at Churt, Surrey, planted in 1964 and already 4 to 5 ft high and twice as wide.
From the Supplement (Vol. V)
C. 'Italian Skies'. – The plant in the garden of the late Lord Morton grew so vigorously that it had to be removed.