One of the most common questions in the Extension Office every spring is “What is wrong with my evergreen? It’s brown.” The browning is most common on the windward (north or northwest) side of the tree or row or the side facing the afternoon sun and is caused by desiccation during the winter months. This can happen in deciduous (trees that drop their leaves in fall) but is most common in evergreens. The reason the problem is more prevalent in evergreens is that the leaf and surface area is maintained all winter to add to the moisture loss when the ground is frozen and it is harder for the tree to replenish moisture.
The brown needles and in some cases twigs, branches and even whole trees will die. Death of the whole tree is more common in young plants that have not yet established a root system to help them access water throughout the winter.
What can be done?
For those branches that are already dry and brown this spring it is too late. Pruning out dead branches may be the only option to make the plant look a little better. Fall preparation is the key to help maintain the tree through the winter months. Water generously just prior to fall freeze and if there is a thaw during the winter, take advantage of the opportunity to water again.
For those newly planted evergreens, build a wind barrier to help them get through the winter. Do not cover them entirely with a plastic bag. This may cause the plant to reach dangerously high temperatures on sunny days that can cause further damage to the tree. There is also a spray with a film type (latex or wax) antidesiccant available to reduce moisture loss throughout the winter.
For more information on winter damage to trees, call the extension office or access the “What’s Wrong with This Tree?” MontGuide on the MSU Extension Publications website at http://extn.msu.montana.edu.
The programs of the MSU Extension Service are available to all people regardless of race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or family status. Issued in furtherance of cooperative extension work in agriculture and home economics, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Dr. Douglas Steele, Vice Provost and Director, Extension Service, Montana State University, Bozeman, MT 59717.
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