The Morello varieties of the cherry form rather open, round-headed tops that need comparatively little pruning if a well-defined stem and top are established when first set in orchard. As a rule, in all parts of the country where they thrive they will bear well without pruning except in the cutting out of dead twigs as they are noticed without regard to season. If at any time quite large limbs are cut the wounds do not heal over as readily as the apple or pear and usually form rotten spots, starting the exudation of gum. But the young growth can be shortened without injury where it is desirable to thicken up the top in interior climates, where it is often an advantage.
The duke and sweet cherries are upright in habit, and many commercial growers head back the top of young trees in orchard. In two or three years the natural habit is changed from the spire-shape to that of a round-topped apple-tree form. This plan better shades the stem and large branches, and shades the fruit more perfectly from the sun. The after-pruning consists mainly in taking out dead wood as it appears.
Some of the best native plums on rich soil make so much growth during the early stages of bearing that much of the bearing wood is exposed to the sun and the fruit is spoiled by scalding. This open habit is corrected by cutting back the new growth two or three years in succession. When the heavy-bearing stage is reached, the long growths no longer appear and the only pruning required is taking out the dead wood.
Some of the Japan and European varieties are also thickened in the tops by cutting back half of the new growth in the dormant period for two or three years in succession, when the trees are coming into bearing, to protect the fruit and broaden the tops for shading the stems and main branches. But it is now conceded by growers that cutting back the tops does not increase bearing or size of fruit. Its only value as indicated above is to shelter the fruit and. better shade the stem and branches of some varieties.