MANHATTAN, Kan. – Traditional pruning time in the High Plains is early spring, before trees and shrubs break winter dormancy.

In most cases, however, that tradition benefits the pruner more than the plant, said forester Charles Barden at Kansas State University.

"You can prune anytime to remove obvious storm damage, dead limbs and branches that are growing at bad angles. The important thing is to prune correctly," he explained. "Still, if you want to prune to improve an ornamental plant’s overall shape — its architecture — the last thing you need is leaves, blocking your view."

Another reason to avoid early-season sawing is that some popular Plains trees "bleed" copiously, if pruned before their leaves emerge. The gush of sap doesn’t weaken the trees. It’s mostly water. But it can look ugly — and, rather alarming, Barden said.

"That’s why people can tap maple trees in late winter, when sap is the ‘sweetest’ and makes the best syrup," he added.

Commercial fruit tree growers always time their year’s pruning rather precisely, Barden added. Apple and peach growers, for example, prune not only to improve tree shape but also to reduce bud numbers. That’s how they ensure the remaining flower heads will produce larger fruit. So, they prune after the year’s buds have popped out, but before leaves are fully emerged.

The approach can be a good one for home fruit tree growers, as well, he said. Unpruned apple trees, in particular, can produce so much fruit that its weight puts limbs in jeopardy.

In any case, if homeowners are uncomfortable around power tools and/or don’t have experience in handling heavy limbs safely, they should hire a professional arborist to handle major pruning jobs.

Whether directing or cutting, Barden said, tree owners will need to remember several general rules for pruning:

* Never remove more than one-third of the crown at any one time.

* Remove any major branches that are growing through the crown (i.e., "crossing"), rather than reaching out toward the sun.

* Remove badly damaged limbs and those that are causing rubbing injury.

* When you have to choose, select branches growing at right angles to the trunk. They’ll always be stronger than those with narrow "joints."

* Never "top" a tree. That simply spurs growth of a mass of weakly attached, whip-like branches that fairly quickly will make the tree even taller ... and uglier. If you must shorten a tree, prune back to a limb crotch, making the side limb the new "top."

* Do NOT make pruning cuts that are flush with the trunk. Do NOT leave long stubs. DO prune just beyond the branch’s "collar."

"When I explain that rule to Master Gardeners, I always tell them to look at the palm of their hand as a guide (see illustration at right)," Barden said. "If their thumb’s the branch, they want to remember to cut just outside the wrinkle line at the base of their thumb."

Barden, who handles the forestry side of K-State Research and Extension’s horticulture programs, said trees’ pruning wounds don’t need any special care.

"Research hasn’t found any benefits to applying asphalt tree sealer or tree wax," he said. "Professional arborists like them, though, because sealers make a job look finished. You don’t have to wait until the raw wood ages."