Dwarf fruit trees are both ornamental and productive. In the spring, they produce abundant flowers, and in late summer and fall, a crop of delicious and attractive fruit.
Tree-ripened fruits, especially peaches, are far superior to those in city markets. A dwarf orchard on a plot of land only 60’ by 30’ feet will provide enough fruit for the average family.
Growing Dwarf Apple Trees
Dwarf apple trees have been grown in Europe for hundreds of years by grafting or budding standard apple varieties on dwarfing rootstocks.
The most dwarfing rootstock, Mailing IX, will produce an apple tree that is no more than 7’ or 8’ feet tall at maturity and which will bear about a bushel of fruit.
In this country, dwarfing stocks are often used as an interlock on apple seedlings.
The 6-inch interlock between the seedling stem and the trunk of the desired variety is almost as dwarfing as a dwarfing rootstock but has a stronger root system so that it does not need to be staked to prevent it from blowing over in strong winds.
Planting Apple Varieties
Dwarf apples will begin bearing when only a few years old. Since apple varieties must be cross-pollinated, it is necessary to plant several varieties together to ensure fruit production.
Dwarf apple trees can be spaced 10’ to 12’ feet apart if excessive growth is curtailed. The growth can be checked by root pruning, flattening the branches, or inverting a ring of bark on the branch or the tree trunk.
The roots are pruned by plunging a spade in a circle around the tree at a distance of 1’ to 2’ feet from the base of the trunk.
Training Upright Branches
The fast-growing upright branches can be curtailed and induced to fruit by training the branch in a nearly horizontal position.
This can be done by tying the branches to stakes inserted in the ground or by hanging weights from the branches.
Excessive growth of individual branches can also be checked by inverting a ring of bark about an inch long.
In June, a complete bark ring is removed, replaced inverted, and tied tightly with a broad rubber band.
The inverted bark will unite with the wood in about 10 days when the rubber band is removed.
The cuts must be symmetrical so that the bark fits closely at the upper and lower edges when inverted.
Promote Fruiting
The same technique can be used on 4- or 5-year-old trees to check growth and promote fruiting, but the effect is temporary and if the inversion fails to unite, the tree will die.
Four dwarf apple trees will provide fruit from late summer into the winter. Lodi or Red Astrachan for late summer, McIntosh for fall, and Delicious and Yellow Delicious for winter are good varieties.
Cross-Pollination
Pear trees have long been dwarfed by grafting them on quince rootstocks. As a result, they tend to grow more upright and taller than dwarf apples, but excessive growth can be curtailed by bending the branches outward to a nearly horizontal position.
Most pears require cross-pollination to set fruit, but some are self-fertile. The varieties most reliable in New England are Seckel and Clapp.
Peach trees can best be dwarfed by budding them on Prunus tomentosa, the Nanking cherry, or Primus Besseyi, the Western sand cherry.
We have peach trees on Nanking cherry rootstocks which are only 6’ or 7’ feet tall at the age of nine years, yet produce 50 to 100 large peaches per tree.
They bloom and often produce some fruit when they are only two years old.
The peaches should be thinned to be spaced about 8” inches apart to produce fruit of large size and good quality.
Many excellent varieties are available, and it is possible to have peaches ripening from early August until late September.
Plums can also be dwarfed by budding them on the Nanking or Western sand cherry. In Massachusetts, Burbank and Stanley are superior.
Dwarf Apricot Trees
Dwarf apricots can be produced by using a bridging interlock. However, the apricot cannot be grafted on the Nanking cherry.
It can be grown on the Nanking cherry root by first budding the cherry with peach and budding the peach with apricot the following year.
The 6”-inch peach inter stock serves as a compatibility bridge.
These dwarf apricot trees bloom profusely and are most spectacular in the spring, but they often fail to set fruit in our climate.
Some of the newer varieties are perhaps hardier than, the older types.
Mechanism of Dwarfing
Dwarf trees require the same care as standard fruit trees. The soil must be cultivated and fertilized, the trees must be sprayed or dusted, and they do need some pruning.
But because the trees are small, the spraying can be done without expensive equipment—a hand duster is usually adequate.
All fruit trees require full sun, and most dwarf trees can be spaced 10’ feet apart if properly pruned and trained.
The mechanism of dwarfing fruit trees and the induction of earlier fruiting has long been known.
Dwarfing Effect
The dwarfing effect of girdling the bark, or of certain rootstocks, was explained by Thomas Andrew Knight, the famous English horticulturist, nearly 150 years ago.
According to Knight, “The true sap of trees is wholly generated in the leaves, from which it descends through their bark to the extremities of the roots, depositing in its course the matter which is successively added to the tree. . . . When the course of the descending sap is intercepted [by a dwarfing stock or by girdling the bark], it necessarily stagnates and accumulates above the decorticated space, whence it is repulsed and carried upward to be expended in an increased production of blossoms and of fruit.”
Recent studies, with the aid of radioactive tracers, have confirmed Knight’s observations.
49254 by Karl Sax