|Viburnum subsp. var.|
Viburnum (Viburnum) is a genus of about 150-175 species of shrubs or (in a few species) small trees that were previously included in the family Caprifoliaceae. Genetic tests by the Angiosperm Phylogeny Group showed however that they are correctly classified in the family Adoxaceae.
They are native throughout the temperate Northern Hemisphere, with a few species extending into tropical montane regions in South America and southeast Asia. In Africa, the genus is confined to the Atlas Mountains.
The leaves are opposite, simple, and entire, toothed or lobed; cool temperate species are deciduous, while most of the warm temperate species are evergreen. Some species are densely hairy on the shoots and leaves, with star-shaped hairs.
The flowers are produced in corymbs 5-15 cm across, each flower white to cream or pink, small, 3-5 mm across, with five petals, strongly fragrant in some species. The gynoecium has 3 connate carpels with the nectary on top of the gynoecium. Some species also have a fringe of large, showy sterile flowers round the perimeter of the corymb to act as a pollinator target.
The fruit is a spherical, oval or somewhat flattened drupe, red to purple, blue, or black, and containing a single seed; they are eaten by birds and other wildlife, and some are edible for humans (though many others are mildly poisonous to people). The leaves are sometimes eaten by the larvae of some Lepidoptera species - see list of Lepidoptera which feed on Viburnum.
|Standard Cyclopedia of Horticulture|
Viburnum (the ancient Latin name). Caprifoliaceae. Ornamental woody plants grown for their attractive flowers, fruits, and foliage.
Deciduous or sometimes evergreen shrubs, rarely small trees, with opposite stipulate or exstipulate lvs.: fls. small, in terminal paniculate or mostly umbel-like cymes; calyx with 5 minute teeth; corolla rotate or campanulate, rarely tubular; stamens 5; ovary usually 1-loculed: fr. a drupe with a 1-seeded, usually compressed stone. In several species the marginal fls. of the cymes are sterile and radiate; such are V. macrocephalum, V. tomentosum, V. Opulus, V. americanum, V. Sargentii, and V. alnifolium, and of the 3 first-named garden forms are known with all fls. sterile and enlarged.—About 120 species in N. and Cent. Amer. and in the Old World from Eu. and N. Afr. to E. Asia, distributed as far south as Java. For a key to the 65 species known from E. Asia, see Rehder, The Viburnums of Eastern Asia, in Sargent, Trees and Shrubs, 2:105-116.
The viburnums are upright mostly rather large shrubs or sometimes small trees with usually medium-sized deciduous or evergreen foliage and white or sometimes pinkish flowers in showy flat clusters or sometimes in panicles, followed by berry-like subglobose to oblong, red, dark blue, or black fruits. The viburnums rank among the most valuable ornamental shrubs. Besides showy flowers and decorative fruits they possess handsome foliage which mostly assumes a bright fall coloring. The plants are of good compact habit. Most of the deciduous species are hardy North, but V. macrocephalum var. sterile and V. obovatum are tender; also V. tomentosum, V. Wrightii, V. theiferum, V. cotinifolium, V. nudum, and V. dilatatum are not quite hardy farther north than New England. Of the evergreen species, V. rhytidophyllum is the hardiest and at the same time one of the most distinct and handsomest species of the genus, with its bold foliage and the large clusters of flowers and fruits; it is hardy as far north as Massachusetts in favorable positions; also V. japonicum stands several degrees of frost, but cannot be relied on north of Philadelphia; V. odoratissimum and V. suspensum are still tenderer. The viburnums are well suited for borders of shrubberies or planting along roads, and the more showy ones are handsome as single specimens on the lawn. They are mostly medium-sized shrubs, 5-10 feet high, but V. Lentago, V. prunifolium, and V. rufidulum sometimes grow into small trees, 30 feet high, while V. acerifolium hardly reaches 5 feet. The most decorative in fruit are V. Opulus, V. dilatatum, and V. Wrightii, with scarlet or red berries which remain a long time on the branches. Besides the snowball forms, V. dilatatum, V. tomentosum, V. Sieboldii, V. prunifolium, V. rufidulum, V. venosum, and V. dentatum are very handsome in bloom. Varieties with all the flowers of the cymes sterile and enlarged are known in the case of V. Opulus, V. tomentosum, and V. macrocephalum, the common, the Japanese and the Chinese snowballs; all these are very showy. One of the most charming in bloom is V. Carlesii on account of its rather large pink-and-white and deliciously fragrant flowers which appear in dense clusters early in spring before or with the leaves; almost all other species bloom after the leaves. The foliage of most species turns purple or red in fall, that of V. Opulus, V. americanum, and V. acerifolium being especially brilliant. V. dilatatum assumes a dull yellow color. V. macrocephalum and V. Sieboldii keep the bright green of their foliage until late in autumn. The viburnums are not very particular as to soil and position, but most of them prefer a rather moist and sunny situation. Some, as V. acerifolium, V. Lantana, V. dilatatum, V. Tinus, V. pubescens, and V. prunifolium, grow well in drier places, while V. alnifolium and V. pauciflorum require shade and a porous soil of constant moisture. V. acerifolium does well under the shade of trees in rocky and rather dry soil. V. Tinus is often grown in pots and thrives in any good loamy and sandy soil. With a little heat it may be forced into bloom at any time in the winter; if not intended for forcing, it requires during the winter a temperature only a little above the freezing-point and even an occasional slight frost will not hurt it. The common and the Japanese snowball are also sometimes forced and require the same treatment in forcing as other hardy shrubs.
Propagation is by seeds sown in fall or stratified; also by greenwood cuttings under glass, especially V. tomentosum, V. macrocephalum, V. venosum, V. cassinoides, and the evergreen species; V. dentatum and V. Opulus and its allies grow readily from hardwood cuttings and all species can be increased by layers; grafting is also sometimes practised, and V. Opulus, V. dentatum, and V. Lantana are used as stock.
The familiar snowball is seriously attacked by aphids. Fortunately its place can be taken by a Japanese species that is even more satisfactory. (Fig. 3923.) The berries of its fertile type, V. tomentosum, are a brilliant scarlet, changing to black. The foliage of this snowball is also remarkably beautiful. The leaves are olive-green with brownish purple or bronzy margins, and their plicate character makes them very distinct and attractive. The bush is entirely free from insect pests. The single and double forms of the Japanese species differ as shown in Figs. 3922 and 3923. Unfortunately these "single" and "double" forms have been confused in many nurseries, and only the trained eye can tell them apart in the nursery row. The double or snowball type is, of course, the one destined to the greater popularity, though the single form is a shrub of great value, especially for large estates and parks. The double form is known to nurseries as V. plicatum, but its proper name is V. tomentosum var. plenum. While it is hardy in New England, it is not a shrub that can be transplanted as easily as many other species. Hence it should be transplanted every second year in the nursery until it is sold. The double form may be propagated by cuttings of half-ripened wood in close frames, or by layers, which in some soils would better remain two years. French nurserymen propagate it by layering. The layers seem to suffer from winter and, to be on the safe side, it is best to cover them well with moss or leaves when the ground is somewhat frozen, so that the frost may be kept in until spring. The clusters are about as big as oranges and pure white. They are in great demand for Decoration Day in New York. The single form, unlike the double, is easily transplanted. It is also readily propagated by layers or cuttings. Both kinds are hardy in the North and make compact bushes 6 to 8 feet high.
V. betulifolium, Batal. Allied to V. Wrightii. Lvs. ovate to rhombic-ovate, coarsely serrate, glabrous except a few hairs on the veins beneath, 1 1/2 - 3 in. long; petioles about 1/2 in. with small stipules: infl. 2-4 in. across: stamens longer than corolla: fr. red. Cent. and W. China. S.T.S. 2:147.— V. bracteatum, Rehd. Allied to V. pubescens. Lvs. orbicular-ovate, obtusely sinuate-dentate, pubescent on the veins beneath, 2-5 in. long; petioles about 3/4 in. long, stipulate: infl. 1 1/2-3 in. across, with conspicuous bracts: fr. ovoid, bluish black. Ga. S.T.S. 1:68. Hardy at the Arnold Arboretum. — V. buddleifolium, C. H. Wright. Allied to V. Lantana. Densely stellate-tomentose: lvs. oblong-lanceolate, pubescent above, grayish tomentose beneath, 3-6 in. long: infl. dense, about 3 in. across: fr. ovoid, black. Cent. China.—V. burejaeticum, Regel & Herder (V. burejanum, Herder). Allied to V. Lantana. Lvs. short-petioled, oval or ovate, acute or obtuse, denticulate, with anastomosing veins, sparingly pubescent beneath, 1 1/2 - 3 in. long: infl. Dense, 1 1/2 - 2 in. across: fr. ovoid, bluish black. N. China, Manchuria, Gt. 11:384.— V. cinnamomifolium, Rehd. Allied to V. Tinus. Evergreen: lvs. elliptic-oblong, 3-nerved, nearly entire, glabrous, 3-5 in. long: infl. loose, 5-7 in. across: fr. ovoid, 1/6 in. long, shining bluish black. W. China. S.T.S. 2:114.— V. cordifolium, Wall. Closely related to V. alnifolium, but without radiant fls.: cymes loose, 2-6 in. across: fertile fls. larger: lvs. usually narrower. Himalayas, W. China. S.T.S. 2:138.— V. coriaceum, Blume-V. cylindricum.— V. crassifolium, Rehd. Hardy evergreen species: lvs. deep green, slightly toothed around margins: infl. white, with 5 prominent anthers, chocolate-colored. China.—V. cylindricum, Hamilt. (V. coriaceum, Blume). Evergreen shrub or tree, to 50 ft., glabrous: lvs. oval to oblong, acuminate, usually remotely toothed above the middle, 3-8 in. long: infl. 2-4 in. across, rather dense: fls. white or pinkish, tubular, 1/5 in. long; stamens exserted: fr. black, ovoid. Himalayas, W. China, G.C. III. 52:371. S.T.S. 2:143.— V. dahuricum, Pall.-V. mongolicum.—V. dasyanthum, Rehd. Allied to V. Wrightii. Lvs. ovate to oblong, acuminate, nearly glabrous, 2-5 in. long: infl. lax, 3-4 in. across; pedicels, ovary, and outside of corolla villous: fr. red. Cent. China. S.T.S, 2:149.— V. Davidii, Franch. Allied to V. Tinus. Evergreen, compact shrub, to 3 ft.: lvs. elliptic to elliptic-obovate, short-acuminate, 3-nerved, 2-6 in. long: infl. dense, 2-3 in. across: fr. blue, ovoid, 1/4 in. long. W. China. R.H. 1913, p. 375. J.H.S. 38, p. 63 (fig. 44). G.M. 55:273.— V. densiflorum, Chapm. Closely allied to V. acerifolium. Lower: lvs. smaller, 1-2 in., with mostly shorter lobes or none: cymes denser. W. Fla.— V. ellipticum, Hook. Shrub, attaining 5 ft., allied to V. acerifolium, but lvs. not lobed, oval to elliptic-oblong: fr. oblong-oval, almost 1/2 in. long. Wash. to Calif.— V. erosum, Thunb. Allied to V. Wrightii. Lvs. oblong-ovate or oblong-obovate, pubescent on the veins beneath, 2-3 1/2 in. long; petioles short, stipulate: cymes long-peduncled, loose, 2 1/2 – 3 in. across: fr. Red. Japan. G.F.9:85.-V.fragrans, Bunge. Allied to V.suspensum. Lvs. deciduous, obovate-oblong, sharply dentate, glabrous beneath: panicles with or before the lvs., about 1 1/2 in. long: corolla salver-shaped, nearly 1/2 in. long, fragrant, white, pinkish in bud. N. China. Recently intro. and hardiness not yet tested, but probably fairly hardy as far north as Mass.; very floriferous and in bloom apparently one of the handsomest viburnums.—V. furcatum, Blume. Closely related to V. alnifolium, but of more upright habit and stamens shorter than corolla: seed with the ventral furrow more open and broader. Japan. S.I.F. 2:74. S.T.S. 2:119.— V. Harryanum, Rehd. Evergreen: lvs. orbicular to obovate or broadly oval, glabrous, 1/3 - 1 in. long: cymes 1-1 1/2 in. across: fr. black. W. China. Very distinct in its small privet-like foliage.— V. Henryi, Hemsl. Allied to V. Sieboldii. Evergreen, to 10 ft.: lvs. elliptic-oblong to oblong-obovate, acuminate, glabrous or nearly so, shallowly serrulate, 2-5 in. long: panicles broadly pyramidal, 2-4 in. long: fr ovoid. 1/3. in. long, first red, then black. Cent. China. B.M. 8393. S.T.S. 2:116. G.C. III. 48:264, 265; 60:193. R.B. 35, p. 296. Tender.—V. hupehense, Rehd. Allied to V. Wrightii. Lvs. broadly ovate, acuminate, dentate, slightly pubescent above, more densely below, 2-3 in. long; petiole stipulate: cymes stellate-pubescent: fr. ovoid, dark red. Cent. China. Hardy at the Arnold Arboretum.— V. ichangense, Rehd. (V. erosum var. ichangense, Hemsl.). Allied to V. Wrightii. Lvs. short-petioled, ovate to ovate-lanceolate, acuminate, dentate, rough above, pubescent beneath, 1 1/2 – 2 1/2 in. long; petiole 1/4 in. long or less, stipulate: cymes slender-stalked, 1-2 in. across: fr. ovoid, red. Cent. and W. China. S.T.S. 2:150.— V. kansuense, Batal. Allied to V. Opulus. Lvs. slender-stalked, ovate in outline, deeply 3-5-lobed, with coarsely toothed acuminate lobes, hairy on the veins, 1-2 in. long: cymes 1 – 1 1/2 in. across without sterile fls.: fr. red. W. China. A graceful shrub very distinct in its small deeply lobed lvs.—V. lobophyllum, Graebn. Allied to V. Wrightii. Lvs. orbicular-ovate to broadly obovate, abruptly acuminate, coarsely toothed, glabrous or hairy on the veins beneath, 2-4 in. long: cymes 2-4 in. across; stamens longer than the corolla: fr. red. W. China. G.C. III. 60:197. S.T.S. 2:147.—V. mongolicum, Rehd. (V. dahuricum, Pall.). Shrub, to 6 ft.: lvs. broadly ovate to oval, crenate-denticulate, stellate-pubescent beneath, 1 1/2 – 2 1/4 in, long: fls. salver-shaped, in short panicles: fr. finally black. Dahuria to N. W. China. Possibly not in cult.; the plant figured as V. dahuricum in horticultural literature is not this species.—V. orientale, Pall. Allied to V. acerifolium: shrub, attaining 4 ft.: lvs. with simple, not fascicled hairs on the veins beneath and not glandular dotted beneath: fr. red. June, July. W. Asia. Gt. 17:567.—V. phlebotrichum, Sieb. & Zucc. Allied to V. Wrightii. Lvs. short-petioled, ovate to elliptic-ovate, acuminate, glabrous, except hairy on the veins beneath, 1 1/2 – 2 1/2 in. long: cymes slender-stalked, nodding, loose, 1 – 1 1/2 in. across: calyx and pedicels purple: fr. ovoid, red. Japan. S.T.S.2:120. S.I.F. 2:73.—V. propinquum, Hemsl. Allied to V. Tinus. Evergreen: lvs. elliptic to elliptic-oblong or ovate-lanceolate, acuminate, 3-nerved, remotely denticulate, glabrous, 1 1/2 – 3 1/2 in. long: cymes 1 1/2 – 2 1/2 in. across, glabrous: fr. globose-ovoid, bluish black. Cent. and W. China. S.T.S. 2:115.—V. sympodiale, Graebn. Closely related to V. alnifolium. Lvs. narrower, ovate to elliptic-ovate, more finely serrulate and usually rounded at the base, 3-5 in. long: cymes 2 1/2 – 3 1/2 in. across: fr. purple. Cent. and W. China. S.T.S. 2:139.—V. urceolatum, Sieb. & Zucc. Low straggling shrub: lvs. slender-petioled, ovate-lanceolate, crenate-serrulate, glabrous, 2 1/2 - 5 in. long: fls. tubular, scarcely 1/6 in. long, in slender-stalked cymes 1 1/2 – 2 1/2 in. across: fr. ovoid, black. Japan. S.T.S. 2:141. Recently intro.: one of the least ornamental in bloom.—V. utile, Hemsl. Evergreen shrub, to 6 ft.: lvs. elliptic-ovate to ovate-oblong obtusish, entire, lustrous above, densely whitish tomentose beneath, 1-3 in. long: cymes stalked, dense, 2-3 in. across: fr. bluish black, ovoid, 1/3 in. long. B.M. 8174. S.T.S. 2:142. G. 35:380. R.B. 35, p. 280.—V. Veitchii, C. H. Wright. Allied to V. Lantana. Shrub, to 5 ft.: young branchlets and petioles stellate-tomentose: lvs. ovate, acuminate, cordate at the base, remotely dentate, stellate-tomentose beneath, slightly stellate-pubescent above, 3-5 in. long: cymes 4-5 in. across, stellate-tomentose: fr. red, finally black. Cent. China.
Pests and diseases
About 150 species are known, including the following:
Many species of viburnum have become popular as garden or landscape plants because of their showy flowers and berries and generally good autumn colour. Some popular species, hybrids, and cultivars include:
- The hybrid Viburnum × bodnantense (V. farreri × V. grandiflorum) is particularly popular for its strongly scented pink flowers on the leafless deciduous shoots in mid to late winter.
- Viburnum × burkwoodii (V. carlesii × V. utile)
- Viburnum × carlcephallum (V. carlesii × V. macrocephalum)
- Viburnum carlesii has flowers that look somewhat like snowballs, excellent fragrance, dense structure, and reddish leaves in autumn.
- Viburnum davidii is an evergreen species from China with blue fruit, hardy to USDA zone 7.
- Viburnum dentatum has flat-topped flowers, bluish fruit, and reddish leaves in autumn. It is somewhat salt tolerant. The cultivar 'Blue Muffin' is more compact than the species and has fruit that are a deeper blue than the species.
- Viburnum dilatatum has flat-topped flowers, reddish leaves in autumn, and bright red fruit that persist into winter.
- Viburnum × juddii (V. bitchiuense × V. carlesii)
- Viburnum plicatum has white, snowball-like flowers, textured leaves, reddish-black fruit, and can grow quite large under ideal conditions. The species can tolerate shade, but not drought. The variety tomentosum has flat-topped flowers but is otherwise the same as the species.
- Viburnum × pragense (V. rhytidophyllum × V. utile)
- Viburnum × rhytidophylloides (V. lantana × V. rhytidophyllum)
- Viburnum rhytidophyllum is a popular evergreen species, grown mainly for its foliage effect of large, dark green leathery leaves with strongly wrinkled surface. This is the parent species of two popular hybrid cultivars known as 'Alleghany' and 'Pragense'. 'Alleghany' was selected from a hybrid between V. rhytidophyllum and V. lantana 'Mohican' (in 1958, at the US National Arboretum).
- Viburnum setigerum has upright, coarse structure and orange to reddish-orange fruit.
- Viburnum sieboldii has coarse, open structure, flat-topped flowers, reddish-black fruit, and can grow as a small tree.
- Gardening Help at the Kemper Center for Home Gardening
- Standard Cyclopedia of Horticulture, by L. H. Bailey, MacMillan Co., 1963