The Coastal Gardener: Summer fruit tree pruning keeps them the right size

This past winter I wrote two columns about the proper pruning of stone fruits and other deciduous fruit trees. This important chore continues to be one of the more misunderstood gardening responsibilities. I still get comments from readers who say they enjoyed the articles. I promised then that I would mention the value of summer pruning at a later time.

In those original columns, written in December, I remarked that the objectives of summer and winter pruning are quite different, although both important.

Before you prune another branch on your peach, nectarine, plum, apricot, apple, persimmon, pluot, almond or other deciduous fruit tree, take a moment to learn about the unique pruning needs of these trees. Correct pruning will lead to healthier trees, strong structure and delicious yields for decades to come.

Most established backyard deciduous fruit trees need pruning twice a year, with a different purpose at each session. Summer pruning can be done while there is still fruit on the tree, but is most often performed immediately following the harvest. The primary purpose of summer pruning is to manage tree size.

As illogical as it may sound to a beginner, attempting to reduce the size of a deciduous tree with winter pruning is fruitless (pun intended). Winter-pruned trees simply burst out the following spring with a vigor that seems limitless, growing twice as fast as normal. Long, stringy, weak stems bolt to the sky, growing several feet in a few weeks. All that stored energy in the tree has to be released and a 15-foot tree, cut to 10 feet in the winter, becomes a 15-foot tree again very quickly. Pointlessly hacking at your fruit trees in winter, in a futile effort to keep them from getting too large, won’t work, and it’s a common pruning mistake.

Surprisingly, managing the size of a fruit tree is accomplished during the summer. We prune fruit trees in the winter to improve the quality and quantity of the harvest and to create good tree structure. Conversely, the purpose of summer pruning is to manage a tree’s size. Also, if trees receive proper summer pruning, far less winter pruning will be necessary.

It is best to start with a tree that’s the right size for you and your space and then to prune the tree every summer to maintain an ideal size. It is much easier to keep a small tree small than it is to make a large tree smaller. With fruit trees, a good height is usually the height you can reach for thinning and picking while standing on the ground or on a short step.

There are several reasons why summer pruning is the best way to manage a tree’s size. Reducing the canopy by pruning in summer reduces photosynthesis, thereby reducing the amount of new growth, especially the following spring when growth is fastest. Summer pruning reduces the amount of food materials and energy available to be stored in the root system in the fall. This controls vigor the following spring, since spring growth is supported primarily by stored energy. Summer pruning also results in only a small amount of immediate re-growth, since the plant is in a slower rate of growth during the summer.

Summer fruit tree pruning does not need to be complicated or confusing. Don’t let pruning decisions inhibit or slow you down, although do get to know the fruiting habits of your specific type of tree No two experts will prune a fruit tree exactly the same, so don’t get too caught up in the fine details. You learn to prune by pruning!

Start your summer pruning by reducing the length of side limbs to promote new growth. Also remove completely any overly vigorous, upright shoots not needed to create permanent branches. Then cut back the new growth on the tree by half or more, depending on the desired size of the tree. The easiest way to manage a fast-growing variety is to prune often, perhaps even three times each year, once about April or May, once about now and again in the winter.

Remove any broken limbs. Diseased branches should be removed immediately when noticed, and as low as possible to entirely eliminate the disease. Disinfect the tools used to remove these limbs to prevent spreading the disease to other parts of the tree.

Thin fruit-bearing branches enough that you can see light through the tree. At least dappled sunlight should penetrate all the way through the tree. This will encourage flowers and fruit throughout the plant, not in the hard-to-reach top of the tree. When branches cross or are too close together, remove one of them all the way, leaving no stubs that will resprout.

For more about fruit tree pruning, refer to my December columns on the Daily Pilot website: https://www.tinyurl.com/columnone and https://www.tinyurl.com/columntwo.

Or just type the words “fruit pruning” into the search box on the Daily Pilot home page.

RON VANDERHOFF is the nursery manager at Roger’s Gardens, Corona del Mar.

Ask Ron

Question: Will Aspen trees grow here? I love the way the look, but I never see them in nurseries.

Carly, Laguna Beach

Answer: No. Aspens (Populus tremuloides) are accustomed to cool summers and cold winters. When attempted in a hot, mild Mediterranean climate like ours, they sulk, quickly scorch and decline. Not long after, wood-boring pests usually do them in. Sorry, Carly.

ASK RON your toughest gardening questions, and the expert nursery staff at Roger’s Gardens will come up with an answer. Please include your name, phone number and city, and limit queries to 30 words or fewer. E-mail stumpthegardener@rogersgardens.com, or write to Plant Talk at Roger’s Gardens, 2301 San Joaquin Hills Road, Corona del Mar, CA 92625.