As we write this article, it is officially the eve of winter. So what better way to honor the change of season than to discuss proper maintenance for caring for your trees in sub-freezing conditions! Remember, as your trees are not protected from the elements in the cold harsh winter, they remain especially vulnerable. This especially applies to smaller trees that are lacking deep root systems. In this article we discuss different methods for protecting your trees, and ensuring their health and longevity long into the future.
Insulate your Trees
Applying roughly 2 inches of mulch to the base of a tree acts like a layer of warm insulation. This ultimately protects tree roots from extreme temperatures, while also serving to retain water in the soil. Although it may seem counterintuitive, it is preferred to wait until the ground freezes to apply mulch beneath the tree, so that mice or other rodents don’t end up making a home within the mulch.
Planning for Denver Weather Extremes
It is essential to keep newly planted trees watered even throughout the fall until the time when the ground starts freezing. May sure to bookmark in your calendar that Denver’s average first freeze typically falls around October 7th. Since Colorado is a specially prone to dramatic swings and temperature, it is not uncommon to experience warm spells that causes the ground to thaw. In case this does happen, continue watering a newly planted trees during these periods.
It should go without saying that even in the winter months, the Colorado sun can be direct and piercing. For this reason we recommend spraying broadleaf evergreen trees with anti-desiccant, which covers the leaves in a wax-like coating, and helps prevent loss of moisture.
Similarly, these extreme temperatures can cause the tree trunks to thaw out during the day, and to freeze in the evening. Unfortunately, this can cause the bark to crack and rupture, resulting in a condition known as sunscald. To reiterate, it is newly planted trees that are especially vulnerable under these conditions. In order to protect these trees, you can either paint your tree trunks white, or wrap them carefully in tree wrap, starting as close to the base of the tree as possible. Remove the wrapping in the spring as soon as freezing temperatures come to an end (in Denver, this is typically around April or May).
We found a concise video on how to wrap trees for winter protection here:
Protection from the Elements
Snow can in fact build up and accumulate on tree branches. Ultimately this can weigh them down and cause them to break. First, you can try gently pushing the snow off of low-hanging branches, while being careful not to break them. If the snow seems to have frozen into ice, try taking a garden hose with warm water and melting the ice down.
Critters such as rabbits and voles love to chew away at the inner and outer bark of trees, and if are allowed to do this for long enough, may cause permanent damage (i.e your newly planted trees may not survive). Protect yourself against these rodents by wrapping your trees with plastic tree guard (in the same manner as you would with tree wrap). Once the spring comes around, rodents will have better things to do than to gnaw on the bark of your trees, and it will be safe to remove the plastic tree guard at this point.
The winter may also present you with ideal opportunities to prune your trees. In the absence of foliage, it becomes much easier to spot areas where are your trees require pruning attention. Furthermore, given that many disease-causing organisms lay dormant in the winter, pruning your trees where appropriate may help to prevent the spread of disease. To learn more about pruning, see our article on Simple Pruning Techniques.