When to prune

Most fruit trees, except cherries, are pruned in the dormant season, after leaves have dropped and before blossoms appear. In the Pacific Northwest, this traditionally has been any time from mid-December to mid-April. A deep freeze after pruning, however, can be detrimental to the tree, so if you are pruning before February, keep an eye on the weather forecast before you get out your pruners.

How to prune

The goal in pruning a fruit tree is to create a structure that allows light into the center of the tree and to strengthen branches that bear the weight of fruit. Ideally, you start when the tree is young to create the framework you want.

Most fruit trees require only maintenance pruning once they are mature. But some, such as peaches and apricots, bear fruit on one-year-old wood and need to be pruned vigorously every year to stay productive.

When you prune trees, you either cut out complete branches (thinning) or you cut the ends off branches (heading). For fruit trees, most cuts you make should be thinning cuts, opening channels of light into the center of the tree and helping the fruit ripen.

Thinning means reducing the number of branches rather than encouraging the tree to grow more branches. When you thin-cut a branch, you remove it. But when you head-cut a branch, side branches grow from the site of the cut, and the younger the branch, the more vigorous this extra growth will be.

Pruning first aid

Pruning cuts need not be treated. Pruning wounds made late in the dormant season heal faster than those made earlier, allowing less time for disease organisms to infect the wound. Furthermore, spores of many organisms causing branch diseases are more prevalent with early season rains than later.

The key with thinning cuts is to remove branches flush with the branch collar, but don’t leave a stub — and don’t make the wound larger than necessary, which happens with a “flush cut.” Cut just outside the tapering portion of the branch, where it’s inserted in a larger branch or the trunk.

For pruning technique illustrations, look up the publication “PNW 400: Training and Pruning Your Home Orchard” at skagit.wsu.edu/mg.

When choosing which branches to thin and which to retain, first cut out any dead or diseased wood. Then remove branches that overlap or shade the branches below, and branches that have narrow crotch angles.

For heading cuts, make the cut at an angle so water doesn’t collect on the fresh cut; the drier the cut stays, the better it will heal. Avoid heading cuts unless you want to stimulate branching at the ends of the limbs you are cutting. Remember that trees grow from the top, so branches remain the same height from the ground no matter how tall the tree grows.

Many fruit trees are pruned as vase shapes with open centers. Once mature, they need only annual pruning to maintain the open center by removing excess branches with thinning cuts and cutting out any water sprouts (thin branches that usually grow straight upright). There are a few differences between trees, and the accompanying sidebar offers some specific pruning instructions.

Know & Grow Workshop

Pruning Dormant Fruit Trees

De Arbogast of the Western Washington Fruit Research Foundation will answer specific questions about how to prune your home and backyard fruit trees after they go dormant. Disease prevention and spraying schedules will also be covered.

When: 1 to 2:30 p.m. Tuesday, Nov. 17.

Where: WSU Mount Vernon NW Research and Extension Center, 16650 Memorial Highway 536.

References

Pruning Tree Fruit — The Basics: http://maritimefruit.wsu.edu/Pruningbasics.html

Training & Pruning Your Home Orchard PNW 400: http://extension.oregonstate.edu/catalog/html/pnw/pnw400/

Easy Steps to Fruit Tree Pruning (55-minute video). Order online at http://pruning.com/default.htm

In Spanish: Pruning: http://extension.oregonstate.edu/catalog/pdf/ec/ec1543-s-e.pdf

n Jane Billinghurst is a certified Skagit County Master Gardener. Questions may be submitted to the Washington State University Extension office, 11768 Westar Lane, Suite A, Burlington, WA 98233. 360-428-4270.