Revitalizing Old Fruit Trees

Suppose you have recently acquired property that already has fruit and nut trees growing on it, but the trees have been neglected for several years. Is there any hope? The answer to this question depends on the condition of the specimen to be revitalized.

There are four main objectives when pruning mature trees: 1) to reduce the number and increase the size of the potential crop; 2) to develop new fruit wood; 3) to remove interfering and broken branches and 4) to contain tree height and spread for convenient harvest.

Most fruit trees, when not pruned, produce more fruit than they can size and mature properly. To prevent such overproduction, remove several limbs annually when the trees are dormant (in the winter). Peaches and nectarines require severe pruning yearly. Other fruit trees are intermediate in their pruning needs. Bearing nut trees will produce nuts of adequate size with little or no pruning.

When fruit trees have not been pruned for several years, they become brushy and weak, and stop producing satisfactory fruit wood. Some new fruit wood is necessary each year for most trees to maintain production of good fruit. This is accomplished by annual pruning. Young wood grows rapidly (as much as 40 inches during the year) and old wood grows slowly (as little as 2 inches during the year). The caliper of young wood is thick and old wood is thin. Young wood points upward, but old wood droops. Young wood is straight and non-branched, while old wood is crooked and branchy. Young wood bears large fruit of good color; old wood bears small, poorly colored fruit. For example, peach trees only produce fruit on fruit wood that grew the previous year; therefore, they require extensive annual pruning to develop adequate fruit wood for the following year's crop. Other fruit, such as apples, plums, and apricots, bear fruit on the same spurs for several years. Assuming that the same spurs will bear fruit for five years, sufficient pruning to produce about 1/5 new wood each year is necessary to maintain normal cropping. Some thinning out is also desirable to permit light infiltration so that the fruit wood will stay healthy. Bearing shoots often have too many old spurs. If such wood is "headed back" a 1/2 or even 3/4, the number of fruiting spurs is lessened but the quality of fruit is improved.

Many old trees bear only in alternate years. It is best to prune heavily just before the heavy?bearing year. If fruit buds can be recognized, much thinning of the crop can be done in the pruning operation.

Wind, heavy crops, and disease can break and kill branches. Overcrowding and lack of sunlight also will cause branches to die. Pruning is necessary to remove dead, damaged, broken, diseased and weak branches. Limbs that cross the center of a tree should be removed, too. Cut out the weak, thin wood. Cut out any shoot growth that is pulled down by former fruit crops or is shaded out by stronger shoots. Remove water sprouts each year, as they are non?productive.

Cut old wood out when it begins to weaken instead of letting it continue producing smaller and more poorly colored fruit. The strong new growth remaining will produce fruit similar to that of young trees. In other words, the object is to have young wood on the old tree.

If left unpruned, trees will become too large to harvest. In addition, most of the fruit of unpruned trees will grow in their tops. Once a tree has reached a height of 10-15 feet, it should be pruned annually to keep it at that height. A combination of thinning out and topping upper limbs can be used effectively to maintain reasonable tree height for most fruit trees.

Old unpruned fruit trees often are eye?sores producing few fruits, that are, for the most part small, wormy, and worthless. In most cases, these trees can be rejuvenated, and made attractive in your landscape. An old tree may have several large, tall, primary branches emerging at narrow angles, close to each other. There may or may not be any low side branches. The functional portion of the tree is usually a solid canopy of weak but crowded branches at the top of the tree.

At first sight, pruning one of these old trees may look like an impossible task. But if you keep the following system in mind, pruning becomes manageable:

1. A few large pruning cuts accomplish more than many small cuts. Often the elimination of one or two misplaced, large, primary limbs in the center opens up the tree and gives it an entirely new look.

2. In reducing tree height and opening up the top branches, simply apply this same principle—a few heavy cuts rather than many fine ones. Only one to three cuts on each remaining primary branch may be all the tree needs.

Once pruned, much wood and bush have been cut away from the tree. Such drastic pruning tends to invigorate the tree and brings heavy vegetative growth the following spring. Avoid applying any fertilizer containing nitrogen for at least a year after this heavy pruning.

It takes 2 or 3 years to rejuvenate an old tree. Direct prune by selecting well placed new branches as eventual replacements for the old higher ones. Control excessive shoot growth by thinning out and heading back those that are left. Leave the tree open to be sure that enough light penetrates to its center. This helps promote fruit bud formation on the new interior shoots.

Continue to head back and thin out the top of the tree, gradually eliminating the old top as newer branches begin to take over.

Very old plum trees are difficult to renovate. Old apple trees, if cut back severely, will readily produce new shoots, but this is not true with old plum trees. Any heading back of large branches should be done at a side branch or shoot.

It is possible that some trees are so far gone that there is no salvation and the best choice is to start over with a new tree. So if the trees do not respond with heavy growth the year after pruning, they should be removed. Also, old trees with just a limb or two that is still alive really will have very little productivity and should be removed as well. A new tree can be grown to a productive state in 3 - 4 years or less, so it is not like the end of the world to take out old non?productive trees.