Pruning makes fruit trees more 'fruitful'

A good time to prune fruit trees is in late February or early March before the buds begin to swell. The branching habits are easy to see, and the weather is generally more conducive to outdoor work.

Avoid working in the rain or walking over the root zone of a tree when the soil is soft and wet. Disinfect your tools with Lysol disinfectant or a solution of nine parts water to one part bleach after completing each tree and after each pruning cut if a tree has diseased branches.

A general goal of pruning a fruit tree is to thin the canopy in order to increase sunlight and improve air circulation, which in turn will increase fruit production and help reduce diseases.

First, remove all dead or diseased branches. These are easy to spot, since the wood is generally darker than healthy wood. Then thin the canopy by first focusing on pruning out branches that grow toward the center of the tree rather than out away from the center.

When possible, prune branches that have narrow, V-shaped crotch angles, as they are more susceptible to breaking under pressure than branches with a wider, U-shaped crotch angle. The angle formed by a V-shaped crotch is less than 30 degrees.

Prune out all suckers that arise from the ground next to the main trunk or grow vertically from lateral branches. Try to encourage the growth of lateral fruit-producing branches and discourage upright vertical growth that produces little fruit. Finally, prune out branches that rub against each other or are growing over a walkway, driveway or doorway.

• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.