Fruit trees, bushes and vines are more dependent than any other tree or shrub on proper, consistent pruning. By exposing foliage and fruit-bearing stems to optimum sunlight, you’ll get large, sweet fruit and an abundant harvest.
Start pruning from the time you plant to help develop a strong, balanced framework of branches. The longer you wait, the more difficult the job. Without training, young fruit trees get opposing branches that shade each other and bear poor fruit. While training and pruning means you may wait a few more years for fruit, you’ll be rewarded with a harvest that is vastly superior.
After you shape your young tree, yearly pruning should be done to simply remove deadweight, manage the size and let in the light required for producing limbs. You’ll get better fruit and it will be much easier to spray your plant for pest and disease control.
Prune so that no area of the tree receives less than 30 percent full sun. Once your tree is in full production, growth slows down and you can prune less.
The growth pattern of fruit trees
Fruit trees respond just as landscape plants to thinning and heading cuts. It is important not to cut too much; this will rob the tree of food-producing leaves. Mature trees can handle more pruning, especially thinning, which removes more relatively large branches rather than many small branches.
Fruit trees sometimes produce vertical branches that overtake fruit-bearing wood. Encourage a wide spreading tree because these more horizontal branches produce more fruiting wood and therefore, more fruit.
When to prune
Prune late in the dormant season before the start of new growth, but no later than one week after flowering.
If you can, avoid pruning in summer and fall, as it can rob the tree of the energy it needs to heal wounds, spur buds and extend shoots. Pruning in late fall or early winter can also make trees vulnerable to injury from colder temperatures to come.
You can dwarf a tree that is too vigorous by pruning in early- to mid-August. This should only be done on trees that are three years or older — pruning younger trees in summer can stunt their growth. More mature trees (in the 6 to 8 year range) can withstand summer pruning of about 10 to 20 cuts. Any more will result in smaller, poorer fruit.
Training fruit trees
There are three forms for training fruit trees, each with its own advantages. We won’t get into too much detail here, but the most common for commercial growers is a vase shape. The central leader method is also used, and the modified central leader is a combination of the two.
Start training productive fruit trees when you plant the trees. Pruning and training will help the tree grow into a balanced form. Unpruned, it will become overgrown with weak, twiggy branches and unhealthy fruit.
Once your tree starts producing a real crop, it needs to be pruned differently, depending on where your tree bears fruit — this depends on the type of tree. All fruit-bearing trees can use an annual pruning, with light pruning in the summer to encourage fruit spurs.
Vase Training Pruning— The vase shape is recommended for most home gardens. The tree is shaped to a short, three-foot trunk with three or four major limbs with fully realized secondary branches. Vase training creates an open center so light can reach all the branches. This is always used with apricots, plums, and frequently with apples and pears.
Central-Leader Training— The tree is shaped to a single tall trunk extending up through the tree, with Christmas-tree like tiers of branches along it. The top branches are shorter than the lower branches so light can penetrate it. This form is typical for small dwarf apples, as the tree’s small size make shade and height non-issues. Occasionally, commercial growers use this method for large apples, but it is not recommended for home gardeners.
Modified Central-Leader Training— This combines a strong, central-leading trunk and sunny center of the vase shape. One trunk grows upward with branches like the central-leader. After the third or fourth season (when the tree reaches 6 to 10 feet), the main leader is cut off at 3 to 4 feet. Main branches are then pruned into the vase shape.
Thinning fruit trees
If your tree sets too much of a crop in one year, it can stress the tree and reduce the next year’s crop. That light crop then stimulates another excessive load the next year. Thus begins a vicious cycle of alternate-year bearing.
Thinning the fruit during the heavy years can help, especially with apple trees. Just 4 to 6 weeks after full bloom, your tree starts initiating flower buds for the next season, so it is essential to thin fruit within 50 days of full bloom. The earlier, the better.
How to thin
Thinning a fruit tree is similar to pinching blooms on flowering plants. The goal is to concentrate more energy to less blooms, or fruit. Pull excess fruit off by hand when it reaches 0.5 inch in diameter, then remove the tiniest fruit several weeks later. Take care not to harm flowering spurs on apples or other trees. The fruit stem should remain attached to the spur or branch or injury can result.
To remove the fruit, hold the stem between your forefinger and thumb, pushing off the fruit with your other fingers. Let one fruit per cluster remain, spacing these fruits several inches apart:
- Apples — 6 inches of space between remaining fruits
- Peaches and nectarines — 4 to 6 inches
- Apricots and plums — 2 to 3 inches
- Cherries and pears don’t require thinning