If an apple tree is left unpruned for too long, it becomes overgrown, and as a result, the tree's vigor will be affected, along with its fruit production. A healthy apple tree—much like a peach tree or many other fruit trees—is not one with extremely dense branches and foliage but instead one that has plenty of space and light between the branches.
Faced with a badly overgrown tree, many gardeners fear the restoration will be complicated and are apprehensive about tackling the task. But take heart—it is almost impossible to kill a mature, overgrown apple tree by pruning it. The most complicated pruning takes place in the first three years of an apple tree's life and after this, pruning becomes a pretty easy task. The rewards of a comprehensive pruning job will be better fruit output and a much healthier tree.
When to Prune an Apple Tree
Pruning is best done in late winter while the tree is dormant, or in the early spring before new growth has begun. If possible, avoid pruning in the summer and fall, as this stimulates new, sensitive growth that may be vulnerable to insect attack and winter damage. However, clearly diseased or damaged branches should be removed whenever you spot them.
Mature apple trees will tell you when they need rigorous pruning because the fruit output begins to diminish. Most fruit trees grown in home gardens are spurring types. A spur is a short 3- to 5-inch branch where the apple tree flowers and sets fruit. These spurs diminish when the tree begins to produce suckers and when there is too much unproductive wood on the tree. By removing the suckers and bad wood through heavy pruning, the tree is stimulated to produce more fruiting spurs. And hard pruning also opens up the branches so that sunlight and air can reach all the ripening fruit.
Commercial growers perform some form of pruning on an apple tree almost every year, but for homeowners, a mature tree should be fine if it is hard-pruned every three years or so.
Before Getting Started
Make sure your pruning tools are good and sharp before starting. Struggling to cut with dull tools can lead to accidents on a ladder. Apple trees are spiny, prickly trees that can easily pierce your skin, so make sure to wear work gloves, long sleeves, and long trousers while working.
Equipment / Tools
- Pruning shears
- Lopping shears or saw for larger branches
- Heavy-duty gloves
- Protective gear (safety glasses, hardhat)
- Debris sacks
Remove Bad Branches
Start by removing any obviously dead, damaged, or diseased branches. The dead wood will be dark or brittle, often with the bark falling away and diseased wood is usually a different color than the other branches.
An open wound on a branch is an invitation to insects and further disease, so you should prune out dead and injured wood at any time of the year.
Woody plants are often pruned with the goal of encouraging more growth, but not all growth is welcome. Suckers (branches growing from the base of the tree), whorls (branches that grow from and encircle another branch), and water sprouts (thin branches that usually grow straight upright) are never going to bear fruit—they just sap energy from the plant. Removing these extraneous shoots early in the pruning process will also help you better see the structure of the tree, making it easier to see where further cuts are necessary.
Remove Low Branches
Get rid of any branches within about 4 feet of the ground. They'll probably be too shaded to produce any apples, and low-hanging branches just invite deer and other animals to nibble.
Remove Problem Branches
Now, prune out any downward-facing branches. They, too, will be shaded and unproductive.
Next, focus on removing any branches that cross or rub against larger branches. As these grow, they will get thicker and heavier, so get rid of them now before they do damage to the "scaffold" branches that form the main shape of the tree.
Remove Competing Main Branches
Step back, and view the tree again. It should have one main vertical leader or central trunk. The leader may be a bit curved if the tree wasn't staked as it grew, or if was bent by the wind. There is nothing wrong with this, but major side branches extending from the leader will have to go. If they are left, they will become competing branches that will distort the shape and openness of the tree. Prune them back flush to the main leader.
Clear Out the Clutter
Now, focus on thinning out the interior branches so that sunlight can reach all of the fruits, and so that each branch sits at a nice, strong angle greater than 45 degrees from the leader. Be ruthless in this operation, but it's best not to remove more than about one-third of the tree's total mass if it's been neglected. If a tree is regularly pruned, each session can involve a reduction of about one-fifth.
Inspect the Tree
Finally, make sure that the upper branches are shorter than the lower branches. The final result should look like a pyramid with well-spaced horizontal branches. There is truth to the old adage that tells us a bird should be able to fly through the apple tree without its wings touching a branch.
The results may look extreme when finished, but the tree will soon bear healthier fruit and be easier to harvest as a result.
Growing Apples in the Home Garden. University of Minnesota Extension.