Dwarfing

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Read about Dwarfing in the Standard Cyclopedia of Horticulture 

Dwarfing. 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-m 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:

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 than½ 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.

Pine.—This is one of the most difficult plants to be treated as a dwarfed tree, although it will hardly result in failure, if taken direct from the mountain or seashore while new young needles are steadily growing. Pines that have suffered through various difficult weather are preferred. About half a year previous to removal, a ditch should be made around the plant. In removing, the main root should be carefully cut off by scissors, leaving its end downward to avoid the resin from accumulating, which otherwise might destroy the tree. For different shapes, the branches are to be twisted to and fro, as shown in the cut (Fig. 1368); bind the part with hemp-palm rope, and pull it moderately toward the trunk with a cord. The special nature of this tree is to dislike the humid earth. Having no pleasing flower or fruit, the pine must exhibit merit in the arrangement of needles or the color of the bark. The best time to transplant is in autumn. For fertilizers, one may use oil-cake or a bone-meal.

Mume (Prunus Mume).—This is different from the Japanese flowering cherry; the beauty of the flower should accompany the picturesque form of the tree itself. The age of the tree is highly regarded. Slender branches as well as grotesque trunks with mossy bark are usually chosen. Hence, all dwarfed Mume plants are raised by grafting. The potting of Mume may take place as soon as the flowers have fallen. The pot is to be kept in shade at least one month, the earth having been thoroughly pressed. To have more flowers, the old roots are destroyed, and the branches cut, leaving a few branchlets. Potted Mume is fertilized with thin liquid manure, oil-cakes or occasionally cow's milk, between December and February.

Pomegranate.—In this plant, the portion of the roots which is close to the main trunk may be exposed to the air. As a dwarfed tree, pomegranate is enjoyed both for fruits and flowers. All new sprouts are to be pinched off, other than those that will produce flowers. Until the fruits have grown larger, one should wait for manuring. For flowers, oil-cake, tankage, or bone-meal are used; for fruits a light fertilizer is used.

Bamboos.—Choose one of the most proper kinds and keep it in a pot for two or three years. Then wait upon several shoots coming up. One year after this, these new bamboos are transferred into other pots. The practice needs much patience and great skill, and it would hardly pay, knowing that the prime age of bamboo is only for four or five years. Issa Tanimura.

Dwarf fruit trees.

Generally speaking, dwarf trees are those which by various means are made to remain smaller than normal trees of the same species or variety. Three means are in common use m dwarfing trees: by growing on dwarfing stocks, restricting the root run, and by pruning to check or suppress the growth of the top. Horticulturally speaking, and particularly as the term is applied to fruit trees, dwarf trees are those which are grown on dwarfing stocks. A discussion of dwarf fruit trees is, then, most largely concerned with dwarfing stocks.

Dwarfing stocks are not modern innovations. For at least three centuries, various stocks have been used to dwarf apples, pears, plums, cherries and quinces. In fact, dwarf fruit trees were quite as common, or even more so, in Europe a century ago than they are at present. They have been grown in America, at least dwarf apples and pears, for nearly a century, during which time in recurring periods they have received much attention from fruit-growers. There is in horticultural literature much data, which, while fragmentary, is still substantial, to guide us in the use of dwarfing stocks and to indicate the value of dwarf fruit trees.

The action of dwarfing stocks is readily explained after a statement of what stocks are. A dwarfing stock is always a smaller, a weaker, or a slower-growing variety or species than the tree to be propagated on it. The top conforms to the roots chiefly because of the inability of the latter to furnish sufficient nutrition. The tree is dwarfed through starvation. Other than in size the trees are little or not at all affected, although minor changes in the fruit and in the bearing habit are supposed to be brought about by dwarfing.

Dwarf fruit trees are propagated by the same methods employed in growing standard trees with preference given to budding dwarfing stocks, whereas standard trees are still largely propagated by grafting. Propagators hold that a better union can be obtained by budding than by grafting, and since it is always difficult to secure a good union between plants as widely divergent as stock and cion in a dwarf tree must of necessity be, budding should have the preference of the two methods. In fact the chief problem in growing dwarf fruit trees is to find a stock with which the larger growing cion can easily be worked and with expectations of a close and permanent union. This brings us to the matter of stocks for the several fruits.

Dwarf apples are commonly grown on two stocks— the Paradise and the Doucin. Both of these, it must be understood, are class names, there being in the literature a dozen or more varieties of Paradise and about as many of the Doucin. Carefully compared, the many kinds in use can be reduced to the French Paradise (Pommier du Paradis), English Paradise, and the Dutch Paradise for the first class, while the Doucin stocks may be grouped under the Doucin, the English Broad-leaved and the English Nonsouch. There is much confusion in the names of dwarf apple stock in nurseries and the grower will be fortunate if he gets what he calls for. Of these two classes, the Paradise stocks make the dwarfer plants and should be used for trees to be kept as true dwarfs and for all that are to be trained in fancy forms. The Douchin stocks are the better for free-growing trees.

Pears are dwarfed by growing on quince roots. Any quince may be used, but the Angers, upon which quinces are commonly propagated, is the best dwarfing stock for the pear. Comparatively few pears can be successfully worked on quince roots because stock and cion do not make a good union. This antipathy is obviated by budding the quince with a pear which unites readily; the next year the untractable variety is budded on the more amenable variety, the resulting tree being thus pear on quince, followed by pear on pear—the "double-working of nurserymen.

There is no question but that the Mahaleb is a dwarfing stock for the cherry, and in Europe, where it has long been used, it is always regarded as such. In America, where the Mahaleb in the last quarter century has all but superseded the Mazzard, a free- growing stock, it is not so commonly known that there is a difference in the size of trees on the two stocks. It must not be understood that the Mahaleb stock gives a true dwarf cherry, but it has a very decided dwarfing effect on either sweet or sour cherries.

Stocks for plums have not been well tested—a statement that holds for all stone fruits. It is very certain, however, that varieties of Prunus insititia, as the Damsons or the St. Julien, the latter one of the best of all plums for a stock, have a dwarfing effect on the varieties of the larger-growing trees of P. domestica, as do also several of our free-growing native species, among which P. americana may be recommended for cold climates. For true dwarf trees, however, the only stocks that give promise are the dwarf natives, of which P. pumila and P. Besseyi have been found to unite readily with several varieties each of either the Domestica or Triflora plums, and to make very good dwarfing stocks for them.

Peaches, apricots and nectarines are dwarfed by budding on P. cerasifera, P. insititia and P. americana. It is probable that all of these fruits, and the cherry as well, can be grown on P. pumila and P. Besseyi as true dwarfs, several experiments having demonstrated that good unions form between the peach, at least, and these dwarf sand cherries. As to whether the union would be sufficiently permanent to make the trees Bo obtained worth while, remains to be seen.

The great advantage of a dwarf tree is its small size, which permits the planting of more varieties of a fruit in a small space. Dwarf fruits, then, deserve, in particular, the consideration of amateur fruit-growers and of those who want small-growing fillers for permanent orchards. Trees of small size are easier to prune, spray, and to care for in every way. Because of the low stature and compact head of the dwarfs, wind causes less injury to trees and crops.

Another very material advantage of the dwarfs is that they come into bearing earlier than the standards. The desirability of early bearing from several standpoints is obvious. Advocates of dwarf fruits very generally assert that the fruit from the dwarf trees is of higher quality, higher color and better flavor. As a generalization, this is not true, though it probably is true for a few varieties of each of the several fruits under consideration. Tests of many varieties of apples on dwarf and standard stocks on the grounds of the New York Agricultural Experiment Station show that more often the fruit from standard trees is the better. Pear-growers have found that comparatively few varieties of this fruit are improved in the qualities named by growing as dwarfs. Size, color and quality of fruit are as likely to be affected deleteriously as beneficially by dwarfing.

Dwarf stocks are much used to adapt varieties to soils. This is the chief value of most of the propagating plants named for the stone-fruits. The true purpose of such stocks must be clearly kept in mind —the dwarfing in this case is a disadvantage attendant upon the use of the stock for another purpose.

The disadvantages of dwarfing stocks, in America at least are rather more pronounced than their advantages. They may be summed up as follows: Nearly all dwarf trees are shorter-lived than standards—the exceptions are very few. All dwarf trees, whether trained in fancy forms or free-growing, need more care than standard trees. The chief items needing extra care are pruning, tilling and fertilizing. It is more difficult to propagate dwarf trees and the cost of the plants is therefore greater, making the cost an acre, with the increased number of trees, much greater. Lastly, it is most difficult to secure trees, especially of apples, on dwarfing stocks that are known to be true to name.

In conclusion, it may be said that we have just passed through one of the recurring periods of interest in dwarf trees in America and that commercial fruitgrowers are more than ever convinced that for the present, at least, dwarf trees are of little value to them. The place of these trees is in gardens of amateurs and on the estates of those who can afford to grow and train them for their beauty as well as for their fruit. There is, however, a possible future for dwarf fruits in commerical plantations, when the refinements of horticulture have been carried far enough to show the special adaptations of varieties of the several fruits to different stocks and when the care of dwarf trees is better understood. U. P. Hedrick.

CH


The above text is from the Standard Cyclopedia of Horticulture. It may be out of date, but still contains valuable and interesting information which can be incorporated into the remainder of the article. Click on "Collapse" in the header to hide this text.


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