Trees look like strong, sturdy structures, and they can be, but they respond very quickly to adverse changes in growing conditions. This can be good, such as when you're trying to save a tree from drying out by giving it more water, but it can also be not so good. When you trim or prune the tree, you need to be careful about the timing. Pruning at different times of the year and at different locations on the tree will have effects that could damage the tree.
You Don't Want Growth at the End of the Season
The tree has a growing season that typically ends at the end of summer or beginning of fall; there are trees with longer growing seasons, but for pruning purposes, that doesn't matter. As the growing season winds down, you want the tree to be able to prepare for winter dormancy. You also don't want to kill any growth on the tree. Yet, if you trim the tree now, you could make it think it was time to grow again. New growth could appear that would only be killed by winter frosts. That could damage adjacent parts of the tree.
You Do Want Robust, Healthy Fruit
Sometimes you must trim the tree, and not trimming would be detrimental. During the growing season, the tree will produce buds, then flowers, and then fruit from flowers that were fertilized. Many trees have very inconspicuous fruit or seedpods with little to no flowering. But fruit trees go all out, producing beautiful blooms. The canopy of a tree bursting with blossoms is gorgeous, but if you leave it that way, the fruit is going to be terrible.
Whenever the fruit trees you have start to bloom, get your pruning shears—or at least your garden gloves so you can pinch off flowers. This is a time when you need to remove flowers (patterns may vary depending on the tree, but every other flower is an example) so that the resources that the tree has to grow can be better divided to produce great fruit. Don't avoid this task if you want good fruit from the tree.
Damage and Death Are the Only Exceptions
The only times when you can prune without regard for the season are when the tree is damaged, dying, or dead. If you're removing dead branches and branches that were partially torn off by strong winds, for example, you aren't going to force the tree to do anything like make new growth because what you're trimming away is already too far gone to affect the tree.
The easiest way to remember to trim (or not trim) a tree is to turn over the care to a tree service like Artistic Arbor Gardens Inc. An arborist can keep track of the trees in your yard and trim those that need trimming at the right time.
