Annual Pruning a Must for Fruit Trees
Pruning is one of the most rewarding tasks of gardening, although there is sometimes a flurry of uncertainty surrounding the activity. In the case of fruit trees, annual pruning is necessary to maximize fruit yield and quality and to reduce insect and disease problems.
The majority of fruit tree pruning is performed when the tree is dormant (late winter to early spring). As a rule of thumb, fruit trees that bloom early in the spring, like peach trees, should be pruned last. Apples, and other fruit trees that flower later in the spring, should be pruned first. Avoid pruning in late fall. Pruning will stimulate new, succulent growth, which is easily killed by cool fall temperatures.
When pruning fruit trees, it is best to begin with the end in mind. That is, decide what you want the plant to look like before you begin cutting.
Although there are many forms to which fruit trees can be pruned, two of the most common are the central leader system and the open center system. Apples and pears in home orchards are most often trained to the central leader system. Peaches and plums are usually trained to the open center system.
Central leader system: Trees pruned to a central leader system resemble Christmas trees in that they are shaped like pyramids. This system results in one central trunk that runs throughout the tree canopy.
Open center system: The open center system is used for trees that put on a lot of leaves, which can reduce fruit set. This system is designed to keep the center of the canopy open, maximizing the amount of sunlight that reaches branches.
When pruning fruit trees, be sure to remove what are referred to as the “three Ds” – dead, diseased, or damaged wood.
It is likely that you’ll see fire blight infections on your apple and pear trees. Fire blight is a disease that kills branches and sometimes entire trees. Wood that is infected will be dark, cracking, and brittle. Be sure to cut well below the damage you see, as the pathogen causing the disease is farther back in the wood.
It is also recommended that you sterilize pruners when pruning trees infected with fire blight, so that you don’t spread the disease. To do this, wipe the blades of pruning shears with a bleach and water solution containing 10% bleach.
When fruit trees are overgrown, be conservative with how much you prune. A general guideline is not to remove more than a third of the canopy at one time. Doing so may be too much stress for the plant to recover. If you’re unsure of how much to prune off, remove smaller amounts over the course of two to three years until the tree is back in shape.
Do not treat pruning cuts. It was once recommended to treat wounds created by pruning with a sealer, but studies have shown that it inhibits a plant’s natural healing process and fosters decay of plant tissue. Given adequate time, a healthy tree will heal itself.
Pruning can be an unsettling experience. But with a little practice, pruning can reward a gardener with bigger, better fruit and healthier trees.
For more information on pruning fruit trees, including the central leader and open center system, download a copy of the NCSU bulletin Training and Pruning Fruit Trees at http://go.ncsu.edu/prunefruit.