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.
Dwarf plants are those that never attain the height or size of the usual or representative individuals of the species. Some dwarfs are "natural," being represented by varieties of prevailingly small size; and these varieties usually reproduce more or less true from seed or cuttings. Thus there are dwarf petunias, lobelias, asters, cannas, peas, beans. Such dwarfing comes within the field of breeding.
The "artificial" dwarfs are produced by more or less arbitrary manipulation, as by grafting on stocks of small growth, heading-in the top or the root or both, by confining the roots, by withholding food and water, and by various forms of contortion and constriction.
Plants are dwarfed to keep them within bounds in small areas, to increase flower-bearing and fruit-bearing in proportion to the size of the subject, to bring all parts within reach and control, to express the skill and satisfy the conceit of the gardener, and to extend the range of interesting plant forms; and plants may be adapted to adverse soils or conditions by grafting on hardy or more reliable roots that may chance to have a dwarfing tendency. Dwarf plants are very useful in flower-gardens and in landscape work. The picturesque dwarfs of the Japanese type are amongst the most curious of plant forms.
The Japanese practice of dwarfing. Figs. 1367, 1368.
The art of dwarfing trees has been long practised among the Japanese gardeners. Some trees are more adapted for this purpose than others. The following have been considered to be most suitable:
Juniperus chinensis variety procumbens. Podocarpus chinensis. Podocarpus Nageia. Tsuga Sieboldii. Tsuga diversifolia. Cryptomeria japonica. Acer palmatum.
Acer trifidum. Styrax japonica. Lagerstrcemia indica. Punica Granatum. Trachycarpus excelsa. Rhapis flabelliformis. Rhapis humilis. Zelkowa acuminata. Millettia japonica. Wistaria floribunda. Wistaria brachybotrys. Prunus Mume. Evonymus alata. Cycas revoluta.
Various species of Japanese flowering cherries, ivies, bamboos, fruit trees, etc.
Before entering into a discussion of dwarfed trees, one should have a clear understanding between the "bonsai" or artistic plant and the "hachiuye" or ordinary potted plant.
There are two styles in which the "bonsai" is presented, one is the planting of one or more tiny trees of picturesque form in an artistic shallow pot; and the other is the representing of a part of a miniature garden or forest embracing trees, shrubs, grasses, mosses, rocks, and ponds. The former is simply an improved or modified potted plant, whereas the latter exhibits an imaginary scene, so that one might feel by glancing upon the pot in a little Japanese chamber as if he were at that moment strolling in such a garden or wandering within forest. A little piece of stone gives an idea of Mt. Fuji, and a drop of water the surface of the Japan Sea. We often suspect the tree, covered with mossed bark, of not more than 1/2 foot in height, would reach the cloud; or it might suggest a wintry landscape brought in amidst scorching summer days to release a man from heat.
The success in raising a valuable "bonsai" depends entirely on the skill of dwarfing the trees, and it requires a long experience. Remember always what the home of the plant was, and treat it according to its habitat. In other words, climate, soil, environment, nourishment, and all other circumstances of its original state should accompany the tree; and the degree of humidity, both in the air and ground, is of prime importance in the dwarfing process. Some have the erroneous notion that the dwarfing is accomplished merely by bending the tree unnaturally. The roots are confined to check growth, without making other alteration. The shape and size of the branches or leaves are affected by the firmness of the earth, the way of watering, the kinds of fertilizer, and the degree of sunshine. Between the leaves there should be ample air and frequent sunshine. Some plants need only slight moisture, and others much. Too wet is worse than too dry. Many are thoughtless in giving water, not considering the condition of the soil. Judicious watering is one of the first requisites to success. For example, after being placed on balconies or terraces in the daytime, the potted plants should be exposed outdoors during the night, if not stormy.
Japanese gardeners use many different fertilizers in accordance with the time of growth, kind of plant, and purposes (i.e., whether for branches or leaves, for flowers or fruits), some of them being: oil-cake, bone-meal, tankage, clam-shells, barn-manures, night-soil, wine lees, tea dregs, cow's milk, rice-bran, fish refuse, iron-rust, and others.
Plants both of "bonsai" and "hachiuye" dwarfs should be repotted every two or three years, in order to destroy the old fibrous roots, and to give a chance for new ones. Otherwise, trees are deprived from taking any nourishment, and will soon die. This practice is to be done in February or March, when the aim of dwarfing is completed; whereas the pruning is to be between April and June, to secure more or even larger flowers.