City Fruit | Grow: Pruning

Parts of this article are excerpted from Fruit Trees by Cass Turnbull and published by Plant Amnesty.

The easiest way to prune a fruit tree is to prune it like other trees—for health and good looks. The following tips apply to all trees—including fruit trees. In addition, special pruning techniques can be used to encourage fruit production.

Some people want to prune their own trees; others want to hire someone to do it. We provide information for both options.

Basic pruning tips

First, and always, take out the dead wood. Be thorough. Then take out some of the worst crossing or rubbing branches—those that start on one side of the tree, head the wrong way through the center, and come out on the other side.

Thin back some branches (even a few big branches), especially toward the top, to increase light penetration and to lower the tree. This helps ripen the fruit lower down and increases air circulation (important in preventing the numerous bacterial and fungal diseases that affect fruit trees). Look for narrow, weak, big-branch crotches. Heavy, fruit-laden branches need to be strong. Narrow crotches are the ones that break.

You could stop here and you would have a pretty good-looking apple or pear tree without too much trouble. It will have fruit. But if you want to do more, read on.

Pruning for production

Before looking at fruit production, we need to understand apical dominance. The last bud on the end of a branch (the terminal bud) releases a chemical that moves via gravity and keeps the buds on down the line rather subdued. Think of it as the boss bud. When you cut off the end boss bud, or even pull it over, the chemical flow is disturbed and the other buds begin to grow.

Nature makes fruit by sending up a young, vertical soft branch. It flowers on the tip, and the flower turns into a fruit. The weight of the fruit pulls this supple branch over. As a branch gets older, it stiffens into a more horizontal position, and the apical dominance of the terminal bud weakens. As a result, buds father down the branch are released to form nice little side branches (laterals) and, on them, tiny ¼-inch branches, called spurs. These tiny spurs have fat flower buds (fruiting buds) rather than skinny leaf buds. We want the laterals and spurs. (In the winter it is the fat-budded spurs on trees that make you think that you are looking at a fruit tree.)

On your tree, those branches situated in a not-too-horizontal position will make more fruit buds, or spurs, than other kinds of branches. You can pull or push new branches into such a position, or you can just start cutting out the ones that aren’t in the right place and leave the ones that are.

You can encourage some, but not all, of your laterals to make spurs by heading (also called tipping back) to two or three buds. This works on pears and apples, but not on cherries. New dwarf varieties of apples, called ‘spur type,’ don’t need to be pruned to make them set up spurs. They do it themselves. In fact, be careful that you don’t prune them off.

If the main branch gets pulled too far over—past 90-degrees—apical dominance is diminished, too many buds are released, and those miserable suckers start charging back up.

In some senses pruning fruit trees breaks all the rules for ornamental tree pruning. You try to keep your tree small, something that should never be done to other trees. Pruners often reduce fruit trees dramatically, which would be extremely bad pruning on a maple or oak. You also head a lot. You head side branches (laterals) to force them to make spurs. You shorten major scaffold branches, especially young ones, with heading so that they won’t swing in the wind and lose fruit. Heading causes these branches to get fatter, or stouter. You need stout branches to hold up heavy fruit. On apples and pears, especially, there is a lot of heading.

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Want to hire an expert?

Make sure the person you hire understands how to prune fruit trees. Many general yard care companies, especially those that trim hedges and radically cut back trees, don’t necessarily know about fruit trees. Even some arborists aren’t experienced with fruit trees.

The Plant Amnesty Referral Service provides referrals to landscape professionals with the necessary skills and experience. Call 206-783-9813 and leave your name, location, phone number and email. Say you have a fruit tree.

Common Pruning Mistakes

Let’s also go over what not to do.

Topping is unequivocally bad for any tree, including fruit trees. The suckers that shoot back up from a topped fruit tree will not only be ugly, they are too busy trying to produce enough leaves to feed the tree to make much fruit.

Dropcrotching to reduce tree height. Many orchardists will radically reduce the height of apple and pear trees using the dropcrotch method of lowering trees. They selectively head back to a side branch of a decent size—say half the diameter of the parent stem. This is hard on the health of old trees and opens them up to rot. Younger (fifteen years or less) trees withstand this height reduction better. While dropcrotching reduces the amount of sucker regrowth, compared to topping, it doesn’t eliminate it. Do not use it as a way to keep your ornamental tree small. Don’t prune too much (no more than one-fourth of the total leaf surface) in any one year. And don’t try to fix it all in one year. If you have a tree that needs a lot of work, do it over several years.