Take precautions for healthy winter trees

Oklahoma

Tree stress during cold conditions can be minimized when the correct precautions are taken, said David Hillock, Oklahoma State University Cooperative Extension consumer horticulture specialist.

"Stresses to the trees can come in a number of forms including lack of moisture, temperature changes, nutrition and rodent damage," he said. "With little control over the weather, tree owners should prepare their trees to withstand harsh weather they may be faced with during winter months."

Hillock said lack of adequate soil moisture is often a major cause of winter damage. All plants, especially narrowleaf and broadleaf evergreens, use water during the winter. Moisture must be available below the frost line or frozen soil.

"During dry winters, broadleaf evergreens such as hollies should be watered about once a month," he said. "Don't forget those growing in above ground containers protected from rain. They need water even during a wet season."

With newly planted trees, especially those with thin bark, it is important to protect the bark from direct sunlight during all seasons.

During the winter months when leaves are absent, young trees are more susceptible to sunscalds, which is the blistering and cracking of the bark, he said.

"To protect the trunk, use a commercial tree wrap such as polyurethane spiral wrap or paper wrap," Hillock said. "The wrap should be applied in the fall, but should be removed prior to trunk growth each spring."

Hillock said trees generally only need to be wrapped during their first or second season after planting.

Trees such as broadleaf evergreens planted in open windy areas may be prone to winter desiccation and require additional protection.

"Temporary protective barriers such as sheets of burlap, lathe fencing and bales of hay can be constructed to provide protection from the drying winds," he said.

It is also important to protect trees and shrubs from animal damage.

A polyurethane wrap, wire mesh collars or rodent repellant paint can be used to avoid damage, Hillock said. Holly, honeylocust, elm and fruit trees are the most susceptible to this type damage.

When there is a severe winter and late spring freezes occur, even well adapted plants may be damaged.

"Winter damaged shrubs should have begun growth by at least June 1," Hillock said. "However, freeze damaged shrubs may begin growth early only to collapse and die with the first hot days of summer."

OSU Extension Fact Sheet 6404, Winter Protection for Landscape Plants, offers more information on how to care for trees during the winter.

Date:1/24/06