The use of dwarf apple- and pear-trees is becoming more general in nearly all parts of the States. Apple on Paradise roots and pear on quince are now popular for amateur use, and even market, in sections where the roots are not liable to be injured by winter. In the prairie States apple-trees budded on Pyrus Toringo and plum on sand-cherry (71. Some Native Stocks that Should be Used) stocks are coming into use, but as yet we have no dwarfing stock hardy enough for the pear.
The dwarf apple- or pear-tree as received from the nursery is usually given a rounded top secured by nursery pruning. Such trees are formed by heading back the one-year-old shoot about one foot from the ground and forming a rounded head by after-pruning. But if an approach to this form is kept up in orchard, continued attention must be given to pinching and heading back. Even the dwarf pear without the annual shortening of the new growth will soon reach undue proportions for a dwarf, even if it does not root from the scion when planted quite deeply.
As the years go on apple-, pear-, cherry-, and plum-trees, trained as shown in Fig. 59, will become as common in this country as in Europe. It is known as simple cordon-training, and with dwarf apples and pears, and small growing varieties of the plum and Morello cherries, it is about as simple and easy as growing grapes on a wired trellis. At first those unacquainted with the system will say that it is an unnatural plan to adopt with trees. But the same may be said of the grape naturally running to the top of tall trees. With the tops all trained to the south, or indeed in any direction, along a road or walk, with the top of one tree meeting the stem of the next one, they form an unbroken growth, giving a handsome effect when loaded with fruit. In starting, the young trees are planted about ten feet apart and grow vertically at first and at proper height are bent for horizontal training along the wire.
Fig. 59. - Cordon-training to the south. (After Bailey.)
The few attempts made in this country by foreign setters have given special satisfaction and pleasure. The stems and branches are covered with a garland of leaves and growth is so checked by the recumbent position of the bearing wood that early fruiting is secured. The exposed blossoms of the stone fruits are also less liable to injury by the weather extremes of spring.
The increased size and beauty of apples and cherries in interior climates when grown so near the ground is a surprise to all foreign visitors.
The annual pruning is in the way of cutting back two thirds of the new growth. The increase in length of the laterals is corrected by the occasional starting of new shoots from near the base, as with the grape.
In the interior States young orchard trees are inclined to make most growth on the north side of the stem and top. This is corrected by summer cutting back on the north side. This checks growth and lessens growth of roots on the north side. If continued lightly on projecting points of growth for two or three years we can secure the most growth on the south side.
This applies to all isolated trees in the prairie States (26. Stem-protection) and to a less extent in all parts of the country where the air is more humid. Even the evergreens and some shrubs in interior climates go out from the line of symmetry by greater length of shoots on the north side. In such cases the balance can be sustained by pinching the points of growth of leading shoots on the north side.