Summer pruning of your backyard fruit and nut trees may not be high on your hot day chore list but pruning them after harvest in July and August has a real purpose. Summer pruning can reduce tree height and overall size making harvesting easier, improve fruit size next year and make dormant season pruning next winter much easier.
First sharpen your pruning tools. As with all pruning, deadheading or trimming, you’ll want to make clean cuts. Using the right type and size pruners or loppers will prevent tearing bark or branch wood. Bypass-type pruning shears (two blades that pass each other) will cut through twigs and branches up to 3/4-inch thick. Because the blades on anvil-type pruning shears (one blade hits against a stop) crush woody tissue, they are best used to cut off dead branches and twigs. Use bypass loppers for thicker branches up to 1 1/2 inches thick and pruning saws for the thickest branches.
When pruning or trimming any tree or bush, take off only one-third of the leaf canopy at any time. Removing more than one-third of the leaves reduces food production for the tree and can severely stress it or stunt its growth. In summer, a lighter pruning is better.
Get out your paintbrush and mix up a 50/50 mix of white latex paint and water to paint exposed trunk and branches to prevent sunburn. Newly exposed inner branches will have more tender wood than outer branches and should be painted right after pruning.
In addition to reducing tree height and overall size, proper summer pruning reshapes the tree branch structure or scaffolding to allow sunlight to reach interior branches which will help next years’ crop fully ripen. Summer pruning that removes congested or crossing interior branches will improve air circulation within the center of the tree and reduce disease and pest insect problems (the pests have fewer places to hide).
One feeding of a higher nitrogen fertilizer is usually recommended after harvest, but cut back on the nitrogen after summer pruning this season to prevent rapid development of new shoots that will just make winter pruning more difficult. Try cutting the recommended rate in half and replacing the other half with a bucket or two of good quality organic compost full of nutrients, beneficial micro-organisms and fungi.
The University of California Agriculture and Natural Resources’ Publication 8057, “Fruit Trees: Training and Pruning Deciduous Trees” is a downloadable free publication which contains basic pruning instructions in clear language, basic drawings, and a short section on summer pruning. UC also offers another shorter downloadable publication, “Pruning and Training-The Big Picture,” available online at The California Backyard Orchard, homeorchard.ucanr.edu. I also like the San Francisco Chronicle’s homeguides.sfgate.com sites on pruning peaches and other fruit and nut trees. The articles are directed to the beginner home orchard grower and offer clear descriptions on how to prune and why.
My favorite pruning manual remains Ortho’s “All About Pruning,” which has great color illustrations and clear, simple pruning instructions for many species of trees and bushes. Unfortunately, the book is out of print but it is often available used online or at used book stores.
Elinor Teague: firstname.lastname@example.org