Fruit tree pruning is an annual cold-weather activity for those who like flowering trees, but also want homegrown fruit.

The best timing for this do-it-yourself plant surgery can vary from year to year. Nonetheless, it follows fairly specific guidelines, according to Chuck Marr, horticulturist with Kansas State University Research and Extension.

“Pruning shouldn’t start until the trees have been fully dormant for several weeks. In Kansas, that often means some time in January,” he explained.

But, pruning when temperatures are below 20 degrees isn’t a good idea, either. That can lead to tree injury, Marr said.

And, somehow the whole process must be complete by early spring — before the trees’ buds swell, yet when temperatures won’t drop below 40 F for 24 hours. Meeting this deadline gives hopeful gardeners time to apply a dormant oil treatment to prevent such pests as scale insects, mites, pear psylla and pear leaf blister mites (some of which can not only ruin a fruit crop but also gradually kill the tree).

“With typical weather — if you can ever call Kansas weather typical — our window of opportunity for pruning can sometimes extend through March,” Marr said. “Because of our weather, however, many fruit growers prefer getting the job done as early as they can.

“I recommend starting with the oldest trees first. Older, larger wood tolerates lower temperatures much better than young trees with narrow branches.”

Pruning in winter allows gardeners to identify undesirable or damaged branches without the cover of leaves.

But, pruning before full dormancy leaves fruit trees vulnerable to winter’s subzero temperatures, the horticulturist said. In contrast, pruning in mid to late winter reduces the likelihood of bark’s tearing. In addition, the pruning wounds quickly heal once spring growth begins.