There are a great many useful species of viburnum and from a decorative point of view they can be divided into kinds grown primarily for their, or for their fruits, or for their foliage. Some are evergreen and some deciduous, and though most will grow well in any fairly fertile soil and are hardy in all parts of the British Isles, a few have special requirements or are just a little tender.
A few species have flowers of two kinds, as in hydrangea, small fertile flowers gathered into a flattish cluster and showy sterile flowers surrounding them. The British native guelder rose, Viburnum opulus, is of this kind and the fertile flowers are followed by shining currant-red fruits (yellow in variety fructuluteo). Normally 8 or 9 ft. high, it has a shorter
variety, compactum, only 4 to 5 ft. high. It also has a variety, sterile, in which all the flowers are sterile, forming large white balls, hence it is known as the snowball tree. All forms flower in June as does the Japanese snowball, V. plicatum, which has smaller but equally effective flower clusters. A form of this with some sterile.
Some fertile flowers is known as V. plicatum tomentosum. The flat flower clusters are carried all along more or less horizontal branches and it is a notably decorative shrub but one which needs a fair amount of space to do itself justice.
Other kinds with the ball-like type of flower head are V. macrocephalum, which is just a little tender and needs a warm, sunny place, and V. carkephalum, a hybrid between it and V. carlesii, quite hardy with scented flowers.
Then there are numerous species with quite normal flower clusters entirely composed of fertile flowers. Most of these are sweetly scented and they include V. fragrans (also known as V. farreri), white, to 8 ft., flowering in winter; bodnantense, pink, to 9 ft., also flowering in winter;
burkwoodii, white, evergreen, 5 ft., flowering in late winter and spring; carlesii, similar to the last but deciduous and spring flowering; juddii, yet another in the same style, also deciduous, and by many considered easier to grow than carlesii, and V. utile, white, evergreen, flowering in May.
Viburnum betulifolium and V. lantana, the latter the British, wayfaring tree, are grown primarily for their berries, small and currant red in the first which makes a big bush with arching, red becoming black in lantana which is stiffer in habit and thrives particularly well on chalk.
Viburnum tinus, the laurustinus, is a big bushy evergreen, to 8 ft. high with clusters of white flowers in winter and spring. It will thrive in sun or shade and can be used as a hedge or windbreak. It does well in town gardens and by the sea.
Viburnum rhytidophyllum has the largest, evergreen, wrinkled and dark green above, covered with rusty coloured down beneath. It can reach 10 ft. and is a very handsome foliage shrub. In the common form the flower clusters, which come in May, are a rather dull white, but there is a variety roseum with rose-tinted flowers which are more decorative. Another evergreen species, V. davidii, is also grown primarily for its foliage, but it is very different in appearance, only 2 or 3 ft. high, wide spreading with ribbed dark green leaves. The small white flowers are sometimes followed by good crops of small turquoise berries.