The young nursery tree usually needs some pruning of the top prior to planting with a view to giving proper height of stem and shape of top. It is now generally believed by experienced planters that a fruit-tree stem should not exceed three feet in height. Even in California the low-stemmed citrus and other fruit trees are preferred. If not high enough to work under, still shorter stems are desirable in the northern prairie States. The most desirable shape of top as to spacing of the limbs is shown at Fig. 58, at (A) as received from the nursery, and at (B) one year later in orchard when cut back and properly pruned. Prior to heeling in or setting out, the ends of bruised or broken roots should also be pruned with a sharp knife to favor rapid and more perfect healing.
Fig. 58.—.A, Tree as received from nursery; B, same tree after one year shaping in orchard.
It is now generally conceded that nearly all varieties of the orchard fruits give increased crops of more perfect fruit when alternated in the rows with a view to securing cross pollination. The general record has been that orchards planted with mixed varieties are far more productive than blocks planted with a single variety. Indeed, many varieties of the cultivated fruits are not capable of self-pollination. While we have much yet to learn relative to this subject, enough is positively known to reach the decision that it pays to alternate all varieties of the orchard and small fruits in planting, except possibly the perfect-flowered strawberries and this is not certain with all varieties, as we have secured better crops and more perfect berries from the perfect-flowered Charles Downing when alternated with a good staminated variety. Darwin's great work on "Cross- and Self-fertilization in the Vegetable Kingdom" was at first received with many doubts by fruit-growers, but during recent years his axiom, that "Nature abhors self-fertilization," has been quite fully verified by scientists and practical horticulturists.