This section is from the book "The Standard Cyclopedia Of Horticulture Vol2", by L. H. Bailey. See also: Western Garden Book: More than 8,000 Plants - The Right Plants for Your Climate - Tips from Western Garden Experts.
(ancient Greek name). Rhamnaceae. Ornamental woody plants grown for their profusely produced white, blue or pink flower-clusters.
Deciduous or evergreen shrubs or trees: leaves alternate or sometimes opposite, short-petioled, serrate or entire, usually 3 - nerved, with small stipules: flowers perfect, small, 5-merous, in small umbels forming panicles or racemes; sepals often incurved, colored; petals clawed, spreading or recurved; filaments slender; disk annular; ovary partly adnate to the calyx-tube, 3-celled; style 3-cleft: fruit a 3-celled drupe, dry at length and separating into 3 one-seeded dehiscent nutlets. - Nearly 50 species in N. Amer., chiefly in the Pacific coast region.
These are free-flowering shrubs, some especially valuable for their late flowering period. Many of them are hardy only in the warmer temperate regions, but C. americanus, C. ovatus, and C. Fendleri are hardy North, while the numerous hybrids of C. americanus are only half hardy, and even if protected they are killed to the ground in the North, but the young shoots will usually flower the same season. The safest way, however, to have good free-flowering plants of these beautiful hybrids will be, in the North, to dig them up in fall, store them away in a frost-proof pit or cellar, and plant them out again in spring. Pruning of the late-flowering species will be of advantage; about one-half of last year's growth may be taken away. They grow in almost any soil, but best in a fight and well-drained one, and most of the Californian species prefer a sunny position. Propagated by seeds sown in spring and by cuttings of mature wood in autumn, inserted in a cold-frame or greenhouse; softwood cuttings also grow readily if taken in early spring from forced plants.
Sometimes increased by layers, and the varieties and hybrids by grafting on roots of C. americanus under glass in early spring; the cions must be fresh and with leaves, taken from plants kept in the greenhouse during the winter.
Fig. 847. Low, erect shrub, to 3 ft.: leaves ovate, usually acute, finely and irregularly serrate, bright green and dull above, paler and pubescent or nearly glabrous beneath, 1 1/2-3 in. long: flowers in terminal and axillary panicles on slender peduncles, forming large, corymbose panicles. July-Sept. From Canada to S. C. and Texas. B.M. 1479. Gt. 61, p. 92. Gn. 56, p. 137. - Common in dry woods and making a profusion of bloom, which, however, is short-lived. Many hybrids have been raised from this species in Eu. (see C. hybridus). variety inter-medius, Trel. (C intermedins, Pursh), has smaller, ovate or ovate - lanceolate leaves and the flowers in small, very slender - peduncled, short racemes or panicles. Tenn, to S. C. 2. ovatus, Desf. (C. ovalis, B i g e 1.). Low shrub: leaves elliptic to elliptic-lanceolate, obtuse or acute, crenulate-serrate, nearly glabrous, glossy above, 1-2 in. long: infloresence like the former, but usually smaller. New England to Colo, and Ala.
Fig. 847. Ceanothus americanus. (X 1/3) in. long: flowers blue, rarely white, in narrow panicles, about 3 in. long. May-July. Ore. to Calif. B.R. 30:38. S.S. 2:64. G.C. III. 20:363; 37:179; 41:221. Gn. 74, p. 303. G.M. 50:430. - A very fine, free-flowering species of beautiful blue color. Probably natural hybrids of this species are: C. Veitchianus, Hook. (C. thyrsiflorus x C. rigidus), with deep blue flowers in dense panicled clusters (B.M. 5127; F.S. 13:1383), and C. Lobbidnus, Hook. (C. thyrsiflorus x C. dentatus), with deep blue flowers, in oval, peduncled, solitary clusters. B. M. 4810 (4811 by error). F.S. 10:1016.
ee. Peduncles usually stout, from lateral buds of the old wood.
Tall shrub, with purple or reddish glabrous branches: leaves orbicular to ovate or obovate, obtuse, serrate, nearly glabrous, 1-3 in. long: flowers in rather long, narrow panicles, on stout, leafless peduncles, axillary, from branches of the previous year. May, June. Brit. Col. to Calif. B.M. 5177.
dd. Flowers blue or pink, rarely white: leaves usually half-evergreen.
Hybrids of garden origin, chiefly between C. americanus and C. thyrsiflorus, between C. ovatus and C. thyrsiflorus and between C. americanus and C. azureus; the hybrids of the first group may be classed under C. roseus, Koehne, of the second under C. pallidus, Lindl., and those of the third group under C. Arnouldii, Hort. Some of the most distinct are: albo-plenus, with double white flowers; atrocaeruleus purpureus, flower blue, foliage purple when young; Arnouldii, flowers sky-blue, in large panicles; Gloire de Versailles, with bright blue, large panicles (M.D.G. 1903:485); Gloire de Plantieres, flowers dark blue, in large panicles; Victor Jouin, flowers deep blue, darker than in the preceding, one of the hardiest hybrids; Ciel de Provence, flowers deep blue, profusely produced (R.H. 1903:332); Marie Simon, flowers flesh-colored; roseus, flowers pink (R.H. 1875:30); pdllidus, flowers pale blue, leaves green and pubescent below (B.R. 26:20).
Shrub or small tree: leaves oblong, obtuse, crenate-serrate, nearly glabrous, 1-11/2
cc. Foliage tomentose or densely pubescent beneath: half-evergreen or evergreen (see also C. hybridus).
d. Branchlets and the veins beneath nearly glabrous: leaves very obtuse: flowers white.
Tall shrub: leaves persistent, broadly elliptic, mostly subcordate, obtuse, serrate, dark green and glabrous above, canescent beneath, but the veins glabrescent, 2-3 in. long: flowers in large, compound panicles at the ends of the branches. June, July. Brit. Col. to Colo, and Calif. B.M. 5165.
dd. Branchlets and the veins tomentose or pubescent: leaves mostly acute: flowers usually blue.
e. The leaves glabrous or puberulous above, whitish or tawny tomentose beneath.
Small tree, with whitish bark: branchlets at first angled and pubescent, later glabrescent and glossy: leaves elliptic-ovate, obtusish or acutish, rounded or subcordate at the base, closely serrate, with close white tomentum beneath, 1 1/2-3 in. long: flowers pale blue to white in panicles 2-3 in. long. Spring. Isls. off the Calif. coast. S.S. 2:65.
Tall shrub: branchlets terete, densely tomentose: leaves oblong-ovate or oblong, acute or obtuse, rounded at base, serrate, with villous tawny tomentum beneath, 1-3 in. long: flowers deep blue, in slender panicles 2-4in. long. Spring. Mex. L.B.C. 2:110. B.R. 4:291. P.M. 2:74. Gn. 61, p. 223-Under this name, a hybrid species with C. americanus is often cultivation.
ee. The leaves villous or hirsute on both sides, usually green beneath.
Shrub or small tree, with villous branches: leaves broadly elliptic or ovate, rounded or cordate at the base, obtuse or acute, with glandular teeth, 1/2_2 in. long: flowers deep blue to purplish, in narrow panicles 1-2 in. long. April, May. Calif. - Called "wild lilac" in Calif. variety Orcuttii, Trel. (C. Orcuttii, Torr.). Flowers blue, paler: fruit loosely villous.
bb. Margin of leaves entire or nearly so (sometimes serrate on vigorous shoots).
c. Shrub prostrate: flowers white.
Low, prostrate and spiny shrub: leaves oval, rounded or nearly acute at both ends, entire, rarely finely serrulate, grayish green, minutely tomentose beneath, 1/2 - l in. long: flowers white, in short racemes, terminal, on short, lateral branchlets. June, July. From S. D. to New Mex. and Ariz. R.H. 1901, p. 423. M.D.G. 1908:208; 1912:499. - A very graceful and free-flowering shrub of almost creeping habit, well adapted for covering dry, sandy banks; half evergreen and hardy N.
cc. Shrubs tall, upright.
d. Branchlets terete or slightly angled, rarely spiny.
Tall, erect shrub, with glabrescent branches: leaves broadly elliptic or ovate, obtuse, sparingly hairy or glabrous; bright green beneath, 1-3 in. long: flowers blue, sometimes white, fragrant, in 3-6 in. long, narrow panicles. April-June. Wash, to Calif, and S. E. Ariz. B.M. 7640.
Tall, erect shrub, with usually glaucous branches and often spiny: leaves ovate, obtuse or nearly acute, glaucous and glabrous or grayish tomentose below, 1/3-1 in. long: flowers pale blue, sometimes whitish, in 2-3 in. long, narrow panicles. April-June. Calif. Gn. 74, p. 425 (habit).
dd. Branchlets angled, spiny.
Tall shrub, sometimes arborescent: branchlets glabrous: leaves elliptic to oblong, thinly coriaceous, rounded or broadly cuneate at the base, very obtuse or emarginate, scarcely 3-nerved, glabrous, 1/2-1 1/2 in. long: flowers light blue to almost white in large terminal panicles 4-6 in. long. Spring. Cent, and S. Calif., Coast Range and down to sea-level. S.S. 13:621.
aa. Leaves opposite, persistent.
Tall, much-branched shrub: leaves 6patulate or cuneate-obovate, mostly obtuse, entire, minutely tomentose beneath, 1/4-1 in. long: flowers white, in small clusters along the branches. March-May. Ore. to Calif. B.H. 8:170.
Procumbent shrub: leaves cuneate, obovate or spatulate, coarsely and pungently toothed, sometimes only 3-pointed at the apex, often minutely silky when young, 1/2-1 in. long: flowers blue, in clusters, terminal on short branchlets. Spring. Wash, to Calif.
C. africanus, Linn.=Noltea africana. - C. dentatus, Torr. & Gray. Low shrub: leaves oblong, penninerved, dentate, glandular-papillate above, loosely hairy: flowers blue, in peduncled clusters. Calif. F.S. 6:567, 2. B.H. 3:101. - C. dentatus variety floribundus, Trel. (C. floribundus, Hook.). flower-clusters numerous, nearly sessile: leaves smaller. B.M. 4806. F.S. 10:977. I.H. 7:238. B.H. 5:129. - C. foliosus, Parry. Low shrub: leaves small, broadly elliptic, glandular-toothed, slightly hairy, pale or glaucous beneath: flowers deep blue, in numerous small clusters. Calif. - C Iaevigatus, Douglas. Tall shrub: leaves broadly elliptic, serrate, glabrous, glaucous beneath: flowers yellowish white, in large panicles. Calif. - C. microphyllus, Michx. Low shrub: leaves very small, obovate or elliptic, nearly glabrous: flowers white, in small, short-peduncled clusters. - C. papillosus, Torr. & Gray. Low shrub: leaves narrow-oblong, dentate, glandular-papillate above, villous beneath: flowers deep blue, in peduncled, axillary oblong clusters. Calif. B.M. 4815. F.S. 6:567, 1. P.F.G. 1, p. 74 R.H. 1850:321. - C. Parryi, Trel. Large shrub: leaves elliptic or ovate, denticulate, cobwebby beneath: flowers deep blue, in peduncled, narrow panicles.
Calif. - C. rigidus, Nutt. Rigid, much-branched shrub: leaves opposite, cuneate-obovate, denticulate, usually glabrous, small: flowers blue, in small, nearly sessile, axillary clusters. Calif. B.M. 4660 (as C. verrucosus) and 4664. J.F. 3:316; 4:348. - C. verrucosus, Nutt. Low shrub: leaves mostly alternate, roundish obovate, emarginate, denticulate, nearly glabrous, small: flowers white, in small, axillary clusters along the branches. Calif. - C. verrucosus, Hook.= c rigidus Alfred Rehder.