Dwarf Fruit Tree Cultivation

growing low fruit trees, chiefly apple and pear.

In the USSR, dwarf fruit tree cultivation is widespread in the southern regions (where the soil temperature does not drop below — 11°C even in winter). Trees grafted on slow-growing (dwarfing) stock begin to bear fruit sooner than those grafted on fast-growing stock, have higher yields (30 tons per hectare or more), and produce larger, sweeter, and better colored fruits. The small size of the trees in a dwarf orchard eases the task of caring for them and gathering the harvest. Low-growing fruit trees are obtained by grafting ordinary varieties on special slow-growing (dwarfing) stock, by propagating varieties of natural dwarf plants, by limiting the growth of fast-growing trees using surgical methods or chemical agents, or by growing plants in a limited amount of soil (pots, tubs, boxes).

Grafting is the principal method used to grow dwarf trees. Paradise apple is used as dwarfing stock for apple in the southern regions of the European USSR, and red-leaved paradise apple and other stock obtained by Soviet breeders is used in the chernozem zone. With grafting upon such stock, the trees are only 2.5– m tall (dwarf plants). Stock from the doucin group is used to grow semidwarf trees. Forms from the semidwarf group bred in the I. V. Michurin Fruit and Vegetable Institute are being tested in the central regions of the European USSR where the stock from the doucin group is not winter hardy. The main dwarfing stock for pear is quince of various kinds. (Amateur fruit growers sometimes use Juneberry or hawthorn as dwarfing stock for pear.) Fruit trees grafted on dwarfing stock have shallow-growing roots and therefore require highly fertile soil and an ample water supply.

Dwarf fruit trees are used to create uniform tracts of orchards to permit the use of standard cultivation practices; as fillers for orchards of fast-growing trees; to recondition fruit plantations; in reclaiming mountain slopes (where it is easier to care for small trees); in decumbent cultivation of fruit trees, since the small size of the plants makes it easy to cover them for the winter; for tub and forcing culture; and to create shaped trees and espaliers, where the ornamental properties of plants are combined with the presence of fruits. A stepped crown is formed in dwarf trees and a sparse stepped flat crown (green wall) in semidwarf trees.

The artificial shapes of dwarf fruit trees on espaliers—in the form of palmettes, cordons, and so forth—have not become very popular because of the difficulty in breeding them. Other techniques of growing slow-growing trees are rarely used because of their awkwardness (in tubs or boxes) or because they have not been sufficiently worked out (use of chemical agents).