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.
(Greek name of a climbing plant). Ra-nunculacex. Familiar garden plants, prized for their handsome and often very showy flowers followed in many species by attractive feathery-tailed fruits.
Climbing vines, or erect or ascending perennial herbs, more or less woody: leaves opposite, mostly slenderpetioled, usually pinnately compound, lobed, or in some species entire and rarely sessile: sepals usually 4 or 5, sometimes more, valvate in the bud, rarely imbricate, petaloid; petals none (or small in Atragene section, usually considered as petaloid staminodes); stamens many; pistils many: achenes in a head, 1-seeded; style persistent, long, plumose, silky or naked. Fig. 983. - About 150 species of very wide geographical distribution, most abundant in temperate regions. About 20 species found native in N. Amer. and about 80 in E. Asia. Les Clematites, Alphonse Lavallee, Paris, 1884; referred to below by "Lav."-The Clematis as a Garden Flower, Thomas Moore and George Jackman, London, 1872; referred to below by "M. & J."-Clematises, Dr. Jules le Bele, in Bull, de la Societe d'Hort. de la Sarthe; republished in The Garden (vol. 53), June-Oct., 1898. - O. Kuntze, Monogr. der Gattung Clematis in Verh. Bot. Ver. Brandenb. 26 (1885). - A. Gray, Flower N. Amer. 1:4-9, 1895. - Finet & Gagnepain, Contrib. Flower As. Orient 1:1-42 (1905).
The culture of clematises. (K. C. Davis.)
A rich soil of a light, loamy character is the best for clematises, and a little mixture of lime will make it better. The soil must be well drained, and must be kept rich by at least annual applications of horse- or cow-manure. On dry, hot soils cow-manure is best, while on heavy soils a thorough dressing of rich leaf-mold would best serve the purpose. Mulching with half-rotted manure on the approach of winter tends to increase the strength of the plants and the size of the flowers. In dry seasons, spraying is always helpful during the growing period.
Clematises belonging to the Montana, Patens, Florida, and Lanuginosa types should be pruned in February or March, by cutting away all weak, straggling and overcrowded branches. The first three mentioned flower from the ripened wood; it is essential, therefore, that in order to secure blossoms, enough of the strong one-year-old wood should be retained. Viticella, Jackmanii and Lanuginosa should be vigorously cut back, say in November; they blossom from the new shoots. Those of the Patens type should be pruned very little, soon after the flowers have disappeared, by simply trimming off useless branches and seed-bearing peduncles.
Clematises of the vigorous climbing varieties are used in many places to cover walls, root-fences, mounds, arbors, balconies, trellises, small buildings, and, in fact, many other places the ingenious gardener will think of. For pot culture in the greenhouse, and for conservatory walls, the less vigorous species are best suited. All the many varieties and hybrids of the Patens and Lanuginosa types, including Henryi and the forms of Jackmanii, are well adapted to this use, as well as for outdoor purposes. The dwarfer and more bushy species are used in greenhouses to some extent, but are found principally in borders or on large rockeries. Of the latter J. B. Keller says: "Their flowers are not so large as we see them in most of the climbers, yet they are indispensable in the flower-garden, being prolific bloomers and free growers in ordinarily rich, deep garden soil. There is room for improvement in this class, however, and specialists, who hitherto have done so much for the climbers, ought to direct their efforts now to the long-neglected bush clematises.
A noble beginning has been made, resulting in the large-flowering C. Durandii, but we expect more of them in the future." See special notes on culture and hybrid-forming qualities after the descriptions of some of the species and varieties.
The most common method of propagation is by grafting. Roots of C. Flammula or C. Viticella are used; the cions are taken from plants that have been grown under glass, and are used before the wood is entirely ripe. Cions taken from plants grown in the garden in summer are rarely successful. The grafts, in pots or trays, are grown in a moist coolhouse, over gentle bottom heat. Another method of propagation, involving less labor but usually successful, is to take cuttings of nearly ripe wood, grown under glass, and treat them as the cions first above mentioned, without the roots. The latter method is practised preferably in summer in gentle hotbeds; shading, spraying, and later on airing, must be strictly attended to. Layering is practised when large old stools are at hand. The knife is not used in the operation, but a twist of the stem will split the inner bark lengthwise. Every other joint is thus treated, pegged down, and covered with soil. It is best to leave the layers undisturbed until the following spring. Many of the species are often propagated by seed, and many new varieties have thus been secured. The number of hybrids is almost countless; in this account are carefully recorded those in the American trade which are traceable to their origin.
The clematis is subject to a very serious disease, due to the depredations of a nematode worm in the roots. This trouble is most serious under glass and alongside buildings where the ground does not freeze deep. The parasite is probably distributed in the soil adhering to pot-grown plants. It is probable that hard freezing kills the parasite. There is no remedy, so far as known, for affected plants. Using only soil which has been frozen is to be recommended to the propagator.