Preventing Winter Damage

I received a few calls last spring and throughout the summer from homeowners wanting me to look at their trees. Occasionally there was an insect or disease that could be easily found and corrected. However, that was not always the case. Quite often, when looking at tree issues, it is imperative to look back to weather conditions the prior fall or winter and think about what conditions the plant had to suffer through. In an effort to help trees get through the winter without too many problems, here are some tips from Toby Day, our Extension horticulture specialist.

“Withholding water and fertilizer and limiting heavy pruning in the fall will encourage trees to harden off properly. This includes evergreens, such as pine, fir and spruce. Heavy pruning and late fertilizer treatments encourage growth rather than hardening off, so restrain from fertilizing and pruning trees until spring. Throughout the month of September and into October, reduce and even stop watering trees unless they show signs of wilting. Once leaves turn color on deciduous trees and fall off, the trees (including evergreens) are in a dormant state. Once dormant, the trees will not respond to watering. However, after leaves have fallen, it is important to resume watering to saturate soil so that the trees have a water reserve for coming out of dormancy, which could be as early as the first week in January. Following leaf drop, water deeply once a week until the ground freezes.

While many parts of the state experience continual measured snowfall in winter, areas in drier regions may see trees that have suffered even more winter desiccation. Evergreen trees and shrubs show signs of extreme water loss to their needles and twigs following winter. Even though the ground may be frozen, it is a good practice to bring the hoses out periodically and water trees throughout the winter to supply the trees with water - especially during warm periods in winter when the Chinook winds blow.

Protecting newly planted trees from winter desiccation is important. Construct sun barriers for newly planted evergreens on the windward and south side of trees or shrubs to protect them from drying winds and intense reflective winter sun. Tying burlap between fence posts or even propping a wooden pallet on end usually does the trick. Deciduous trees with smooth and dark bark should have trunks wrapped with a tree wrap to reflect the sun, reducing sunscald to the bark.

To learn more about proper tree care, you can download a free MontGuide, a self-learning resource from Montana State University Extension, called “What’s Wrong with This Tree?” at http://msuextension.org/publications/YardandGarden/MT199518AG.pdf or by picking up a free copy at your local MSU county or reservation Extension office.”

While there are no guarantees when it comes to weather, taking these steps now will really help prevent tree problems next spring. As always, if you have questions about any of this, feel free to give me a call at 406-433-1206, or send an email to [email protected].