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.
(name of oriental origin, of no application). Cannaceae. Popular tall ornamental plants, prized for their stately habit, strong foliage and showy flowers; much used for bedding.
Stout, unbranched: flowers mostly red or yellow, in a terminal raceme or panicle, very irregular: caps. 3-loculed and several- to many-seeded (Fig. 779, p.); sepals
(s) 3 and small and usually green; petals (ccc) 3, mostly narrow and pointed, green or colored; style (e) single and long; the stamens are commonly petal-like, oblanceolate bodies or staminodia (aaab), 2 or 3 of which are usually much produced and broadened, and one is deflexed and narrower and forms the lip of the flower (6); the pollen is borne in a single-loculed anther (/), borne on the side of a narrow and more or less coiled stam-inodium. - In the latest monograph, 1912 (Kranzlin, in Engler's Pflan-zenreich, hft. 56), 51 species of Canna are described from subtropical and tropical Amer. and Asia.
A generation or two ago, cannas were grown for their foliage or mass-effect. They were tall and long-jointed, with small and late flowers (Fig. 780). An old-time garden race of tall cannas was C. Annaei, raised by M. Annee, of France, from seeds of the true C. nepal-ensis, sown in 1848. The flowers from which the seeds were taken probably had been pollinated by some other species, most likely with C. glauca. In 1863, a new race appeared, as the result of the union of C. iridiflora with C. Warscewiczii. This hybrid was known as C. Ehemanni (and C. iridiflora hybrida). This was of intermediate stature, with showy foliage and better drooping flowers. Under this name plants are still sold, but they may not be identical with the original C. Ehemanni. This race has been variously crossed with other species and forms, and from innumerable seedlings there have been selected the dwarf and large-flowered cannas (Figs. 781,782), which have now practically driven out the old tall small-flowered forms. These dwarf cannas are often known as French cannas, from the country of their origin; also, as Crozy cannas, from a renowned breeder of them. Within recent years, another race of cannas has arisen from the amalgamation of our native C. flaccida with the garden forms and with C. iridiflora.
These have come mostly from Italy and are known as Italian cannas; also as orchid-flowered cannas. The flowers are characterized by soft and flowing iris-like outlines, but they are short-lived. Of this class are the varieties Italia (Fig. 783), Austria, Bavaria, Burgundia, America, Pandora, Burbank and others. For a sketch of the evolution of the garden cannas, see J. G. Baker, Journ. Roy. Hort. Soc, Jan., 1894; also, for the history of the Italian race, Revue Horticole, 1895, 516, and Gardeners' Chronicle, Dec. 14, 1895; Kranzlin, cited above.
Fig. 779. The parts of the Canna flower.
Fig. 780. Old-time canna.
The culture of cannas is simple and easy. They demand a warm, friable, rich and moist soil. They are injured by frost, and therefore should not be planted out until the weather is thoroughly settled. For dense mass effects, set the plants not more than 1 foot apart each way, but if it is desired to show individual plants and their flowers at the best, give three times that amount of room to a single plant. Pick the flowers as soon as they wilt, to prevent the formation of seeds (which causes the plant to lessen flowering), and keep the plants in tidy condition. Give the soil and treatment that produce the best results with Indian corn.
New varieties are raised from seeds. The seeds usually germinate slowly, and sometimes not at all, unless the integument is cut or filed, or is softened by soaking in water; these precautions taken, they germinate quickly. Sow late in winter, in rather strong bottom heat, in flats or pots. Prick out, and give plenty of room. They should make blooming plants the first year.
Commonly, cannas are propagated by dividing the rootstock. This rootstock is a branchy mass, with many large buds. If stock is not abundant, as many plants may be made from a rootstock as there are buds, although the weak buds produce weak plants. Leave as much tissue as possible with each bud. These one-bud parts usually give best results if started in pots, so that the plant is 6 to 12 inches high at planting time. The commercial canna plants are grown mostly in pots. If one has sufficient roots, however, it is better not to cut so close, but to leave several strong buds on each piece (as shown in Fig. 784). These pieces may be planted directly in the ground, although more certain results are to be secured by starting them in the house in boxes or pots. If strong effects are desired, particuarly in shrub borders, it is well to plant the entire stool. In the fall, when the plants are killed by frost and the tops have dried a few days, dig the roots, and let them dry, retaining some of the earth on them. Then store them on shelves in a cellar that will keep Irish or round potatoes well. Take care that the roots do not become too warm, particularly before cold weather sets in; nor too moist. Well-cured roots from matured plants usually keep without much difficulty.
If they do not hold much earth, it is well to throw a thin covering of light soil over them, particularly if they are the highly improved kinds.