Nearly all varieties of apples—indeed all as far as I know—succeed in this form. The trees are not very long-lived, however. That is they cannot be maintained in good presentable form and prolific bearing indefinitely, because it is difficult to reproduce the fruit spurs on the lower part of the stem. Nevertheless the trees are inexpensive and can be cheaply replaced. As they come into bearing the first or second year after planting, this task of replacing worn-out trees is a small one. Very fine specimens of fruit can be produced on these upright cordons. Indeed this form is superior to the bush form in this respect.
The apple is the best of all trees for horizontal cordons. In this form it becomes the most entertaining plaything in the garden, as well as one of the most rewarding trees in its product of fruit. Either the single arm or the double arm cordon can be used with success. These horizontal cordons are naturally used along the borders of walks, flower beds or plots devoted to vegetables. They may sometimes be used along foundations of buildings, where it is not desired to grow upright cordons or espaliers against the walls. The fruit produced by horizontal cordons is probably superior in size, color and finish to that produced on any other form of tree. In climates where the summer's heat and sunshine are apt to be meager, this advantage of the horizontal cordon will be comparatively greater. Conversely it will be less in places where sunshine and heat are very abundant during the summer. It is probably true that on the plains of Arizona and Texas the horizontal cordon will not be a brilliant success.
Dwarf apples need practically the same care and cultivation, aside from pruning, as standard apples. The soil should be cultivated during the early part of the summer and allowed to rest during the latter part of the year. Cover crops may be sown during June or July, according to the custom practised in the usual orchard management; but the advantages of a cover crop in a small garden are less material than in a large commercial orchard.
FIG. 26—UPRIGHT CORDON APPLES
18 inches apart; in author's garden
The formation of the tree is discussed under another head. It remains to be said only that careful and intelligent pruning are required to keep any dwarf apple tree to its work. The more complicated and the more restricted the form of the tree, the more careful and continuous must be this pruning. The general system may be outlined in comparatively few words, and may be explained in its simplest form as applied to the treatment of a horizontal cordon. Each horizontal cordon, perfectly formed and full grown, should have fruit spurs throughout its horizontal length, which may be from three to fifteen feet. The upright portion of the trunk, from the point where the graft is set to the angle made by the bending down of the stem, should be kept clean and bare. Constant care is required to remove the sprouts from this portion of the tree, especially such as come up from the stock. At the further end of the horizontal portion there should be one, two, or three strong shoots allowed to push forth each year. These may be called leaders. They represent the principal wood growth in each tree. They draw up the sap from the roots, their leaves elaborate this sap, and from them the digested material is sent back for the support of the tree and the ripening of the fruit. They are allowed to take an upright or nearly upright position and their growth is encouraged. On all other portions of the tree growth is sternly restricted, when not altogether repressed.
There is a constant tendency for strong shoots to start into growth all along the horizontal part of the stem and especially near the bend. If any of these shoots are allowed to make headway, the form of the tree is spoiled. Even if they are cut out after a year's growth, thus retaining somewhat the form of the tree, the fruit spurs are thereby lost. It is the business of the fruit grower, therefore, to pinch back these shoots which start along the horizontal stem, and this pinching is done at a comparatively early stage of their growth. Usually the first pinching should be given when the stems have grown long enough so as to have seven or eight leaves. These shoots are then cut or pinched back to three leaves. If the tree is in good vigorous condition, these shoots will soon start into growth once more. Again they have to be pinched. This time the pinching comes a little earlier, taking the shoot when it reaches only about five leaves and the pinching is still more severe. The shoots may start into growth a third time or even a fourth time, but each time they are pinched back sooner and more severely than before. In most cases two or three pinchings will suffice. These constant repressions of growth tend to secure the formation of fruit spurs and fruit buds along the horizontal trunk of the tree.
Some slight modifications of the plan here outlined will develop themselves in experience. In particular it will be found that different varieties require slightly different handling. Some form fruit spurs more readily than others. With certain varieties it is very difficult to repress the rampant habit of growth and to secure a proper formation of fruit buds. These differences, however, are of minor importance as compared with the general management of the tree.