Jan. 17—By Juli Sarris
Colorado Master Gardener
When a polar vortex rolls through Colorado, everyone is miserable, even our poor trees. Dramatic temperature swings, winds and bitter cold can do serious damage. It's not uncommon for the damage to reveal itself much later — even after a year or two. Here are some things you can do to help your trees that do so much for you.
First, give your trees a thorough looking-over. Any cracked or broken branches that you can safely reach should be removed. Use a sharp hand saw and cut directly before the branch collar — the place where the branch joins the trunk (look for rougher bark and a little bulging). If you cannot reach the cracked or broken branch, consider calling a certified arborist for help. Do not, under any circumstances, climb a ladder while you are carrying a chainsaw. This is an extremely dangerous task and should be left to a certified arborist. Check out the website from the International Society of Arboriculture at treesaregood.org to find a certified arborist in your area.
Second, check for vertical splits or cracks in the bark. This can be caused by freezing and then sudden warm weather, a situation we have often in Colorado. If you see vertical splits, a certified arborist will be able to assess the damage and provide guidance as to how to proceed. (Some trees, like the honey locust, have bark that appears cracked when it's healthy, so know your trees before taking action.) Using sealants, tar, paint or adhesives are not recommended and may in fact harm the tree and prevent it from healing itself.
Third, add a note to your calendar to check for damage when the tree starts to leaf out in the spring (for deciduous trees) or put out new growth (for evergreen trees), typically May or June, and then check again the following year. You might see some branches that do not look healthy. These branches may have received damage from the polar vortex that just took a little while to appear. Remove these branches if you can reach them, or contact an arborist.
Give your trees a good deep drink of water — 10 gallons of water for each diameter inch of the tree — during dry winter months on a day when it's above 40 degrees. This will help them survive and thrive and recover from any damage that polar vortexes throw at them.
For more information on this and other topics, visit extension.colostate.edu or contact your local Colorado State University Extension Office.
Juli Sarris is a Colorado Master Gardener for CSU Extension in Boulder County.