Gardening Articles: Edibles :: Fruit & Nut Trees
Pruning Fruit Trees
by Lee Reich
If there's one group of plants that demands regular and careful pruning, it's deciduous fruit trees. Taste the sweetness of a perfectly ripe pear or apricot: That sweetness represents energy. Producing luscious fruits demands lots of energy, which comes from the sun, and one goal of pruning is to help all the limbs on your tree bask in as much sunshine as possible.
Pruning also has other benefits. It's the way to strike a balance between shoot growth and fruit production, so important in ensuring that your tree bears the largest and tastiest fruits year after year. And keeping branches open to light and air also speeds drying of leaves and fruits, decreasing diseases, and allows sprays to penetrate if spraying is needed.
Young Trees: Prune for Form
The first years a fruit tree is in the ground are important to its future performance. It's then that the tree should form its permanent framework. Your goal is to help your tree produce branches that are strong enough to support their future loads of fruit, and to develop branches that won't cross or shade each other. Centuries of fruit growing have spawned many different tree forms, but three predominate: open center, central leader, and modified central leader. The ideal form for a particular tree depends not only on your preferences, but also on the plant's natural growth habit.
Open center training, years one to three
The tree's main stem or stems is called a leader, a continuation of the trunk. A central-leader tree has a leader with branches growing off it; these branches are shorter near the top of the tree. The open-center tree has a vase shape made up of three or four leaders growing off the trunk in an outward and upward direction. The modified-central-leader tree starts with just a central leader, but when it grows to about 7 feet, you stop its growth by bending it over, which slows growth, or cutting back to a weak side branch.
The tree you get from a nursery may be a single upright stem, or whip. Alternatively, you may get a "feathered" tree, an upright stem with some side branches. If your new tree is a whip, shorten it by a third to a half to promote branching. For a feathered tree, save well-placed branches and completely cut away all others. Always cut broken stems and dead or diseased wood back into healthy tissue.
For any of the three basic tree forms, begin branch selection the first season. Start with the first branch about 2 feet from the ground, then space higher ones about 6 to 8 inches apart. Strive for a spiral arrangement of branches so that each branch has room to spread. Also, choose branches that make wide angles (45°F to 60°F) with the central leader, because such branches are most firmly anchored to the stem.
For an open-center tree, once you have selected three or four branches, cut the central stem off just above the topmost branch. The tree then continues to grow upward and outward along the branches, now officially leaders (but not central leaders). As these leaders grow, make sure that none of their side branches originates so low that they interfere with each other.
If your tree is a central-leader or modified-central-leader type, induce the central leader to keep making new branches by cutting off about a third of the previous season's growth each year while the plant is dormant. If dormant-season pruning doesn't produce enough branching options, tip prune leaders during the growing season. Cut back the leader by a few inches each time it grows a few inches above the point where you want a side branch. The uppermost bud that remains after cutting back the leader usually grows to become an upright shoot, a continuation of the leader. Lower buds grow out to produce side branches. Select new side branches that are well spaced along the leader and firmly anchored to it.
The central leader on both central-leader and young modified-central-leader trees should remain as the dominant and most upright stem of the tree--the horticultural top dog. If the leading stem should grow into two equally vigorous stems, remove one of them immediately and completely. Also, don't let the central leader fruit in its first few years and don't let it bend over, because both circumstances would weaken its growth.