Best Time to Prune Fruit Trees Now Here 1/13/05

MANHATTAN, Kan. – 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.

Why Prune Fruit Trees?

Unless they get regular help, fruit trees are prone to damage caused by wind, ice, branch rubbing and awkward growth. To help them develop a strong tree structure, pruning should begin when the trees are planted and continue every year after that.

Even so, some injury will occur each year, due to weather extremes, diseases, insects and the weight of fruit. Removing this damaged wood is important to tree health.

The sun must penetrate a tree’s leafy canopy for its buds to be able to develop and fruit to maturity. So, providing for sunlight penetration is yet another reason to prune.

Most fruit trees also require pruning to keep their size within workable bounds – in both branch spread and tree height.

-- Source: K-State 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.

“Besides, you’re more likely to get total coverage with a dormant oil treatment after you’ve cleared out some of the wood,” Marr said. “Plus, you’ll avoid the waste of spraying wood, only to prune and discard it.”

Information on how to prune fruit trees is available at all county and area K-State Research and Extension offices, as well as on the Web at http://www.oznet.ksu.edu/library/hort2/c631.pdf .

K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus, Manhattan.