One of the keys to producing good quality tree fruit is knowing how to prune. Pruning helps maintain tree health and encourage fruit production. It can even bring a neglected unproductive tree back into fruiting. The aim of pruning during the first several years of tree establishment is to create the shape and the 'backbone' of the tree. After that, pruning serves to correct damage and promote continued healthy and productive growth. The three most common training systems are central leader, modified central leader, and open-center. Intensive production training systems are often called espalier. Espalier usually require supporting structures such as wires, fences, walls, or stakes, but they may also be free standing. There is a wide variety of training forms for espaliered fruit trees. With a few exceptions, prune during the dormant season, from January to March. For routine maintenance pruning of all fruit trees, first remove any suckers growing from the base of the tree. Next, remove any diseased, insect damaged, or broken twigs and branches. Also remove branches that rub against or cross over others and undesirable vertically growing branches.
For apples and pears, the most common home gardening system is the central leader system. Start out by pruning back the whip to about three feet at planting. This will stimulate buds to grow near the top of the cut.
In the second year, select one vertically growing branch to be the central leader and about four other branches to be the scaffold limbs. Select scaffold branches that are at different heights on the trunk, attached at wide angles to the main stem, and spaced evenly around the tree. Use wood spreader blocks where necessary to create wider branch angles in the early years of training. In subsequent years, prune the tree to grow into a pyramid shape.
Open-center training is often used for homegrown peaches and plums. To develop an open-center tree, first cut the whip back to two to three feet high at planting time. Again, this stimulates top buds to grow into branches. In the second year remove all but three to five main branches that are six to eight inches apart, growing from the trunk at wide angles, and spaced evenly around the trunk.
After these first few years, start using pruning methods specific for the species of fruit, as described below, combined with any necessary maintenance pruning. In apples and pears, promote fruiting with spur pruning and renewal pruning techniques. Depending upon the condition of the tree, these techniques can be used alone or in combination.
Fruiting spurs are stubby branchlets that form naturally, but proper pruning can increase spur formation. To prune for spur development, cut back lateral (side) branches arising from scaffold limbs to about four buds. The lower buds on these laterals will become flower buds (rather than vegetative buds) during the growing season. The following winter, cut back all new growth to the uppermost flower bud. A flower bud will be plumper than a vegetative bud. This technique creates a flowering spur that will fruit the following summer and be self-renewing.
Renewal pruning is a useful technique for older or neglected trees. It takes advantage of the tendency of apples and pears to produce flower buds on unpruned two year old wood. Leave strong lateral branches on the outer parts of the tree unpruned during the first year. During the second growing season, these laterals will send out new vegetative growth from the tip. The rest of the buds from the below that point will become flower buds. The following winter, cut back these lateral branch to the topmost flower bud. The lateral will then flower and fruit that year. After fruiting, retain this lateral as an elongated spur, or cut it back to one inch from the base to stimulate the formation of a new lateral branch to repeat the cycle.
In peaches and nectarines, fruit forms on twigs made during the previous summer. The goal is to have new shoots coming each year to bear the following year's fruit. In the dormant season, prune the branch that bore fruit back to one selected new side shoot. As trees come into full bearing age, keep them healthy and well-fertilized so they will produce an abundance of new shoots. It is important to thin out new fruiting shoots to make them evenly spaced, and to allow light to penetrate into the center of the tree. Thinning also prevents overloading that can break branches and promotes new shoot growth for the following year.
Plums and cherries generally need less pruning than other tree fruits. Plums fruit on one year old shoots and spurs that have formed on older wood. Prune plums selectively to maintain an open center and yearly growth of new fruiting wood. Sweet cherries require only maintenance pruning. Sour cherries do best with a modified central leader system. Start training sour cherries when the tree is very young to avoid harmful heavy pruning later on.
KP, WA, entered 1999-12-17