Mark McCauley, Resource Conservationist
Do trees and other plants get thirsty in the winter? Well, it depends on the weather conditions, but I would say usually, especially newly planted trees. Older established trees have a more extensive root system and are more resilient to dry winters. Since we recently had a tree sale this past Fall, I will concentrate on “new” trees as opposed to older established trees, however even older trees can experience winter drought issues.
Although trees go dormant during winter months, their root systems still need adequate moisture and can suffer from lack of it. Regarding evergreen trees, which keep their needles throughout the winter, watering can be even more important, as they lose moisture through their needles faster than deciduous trees, which lose their leaves in the Fall.
So, when should you consider watering? Well, you should water your newly planted trees on a regular basis up until freezing temperatures, for sure, but then also about 2 times per month during the winter, if there is no snow cover on the ground or little precipitation. It is also recommended that you water on days when the temperature is at least 40 degrees (with no snow or ice around the base of the tree), and do so in the morning so the tree roots have time to absorb the moisture before temperatures potentially drop back into the freezing range at night. If it is a windy, dry winter, this is even more critical. Trees that have experienced winter dryness may still look normal the next spring, but the damage may become apparent later in the summer with dieback of branches.
Mulching with a good organic material will also help your new trees conserve moisture going into the winter, and weather the hard freezes better too. However, keep in mind that mulch should not be piled up around the base of the tree like a small volcano, but more like a flat doughnut shape, leaving a “hole” (or space) around the base of the tree. Stacking mulch up against the bark of the tree, which is meant to be above ground, can encourage disease and pest problems which can more easily enter the bark than the root system.
You may find it suitable to carry water to your trees, but a hose may be easier if you have access to it. Laying a soaker hose around the base of the tree is also an option, but whatever hose you do use, remember to drain it and put it away, as frozen hoses are a pain to deal with.
So far this winter, we have seemed to have quite a bit of moisture, so watering may not be a need in your location yet, but that could also change quickly. One method you could use to check soil moisture is to dig a small hole down at least 2 inches within the “dripline” (diameter of the crown spread) of the tree and feel the soil. If is feels damp, the tree should be fine, but if it feels dry, then watering might be needed.
I know gray wintery days might not seem like the time to water, but if it is a dry ground, windy type of winter, it could be very important. You invested time and money in your new trees, so be sure to take the necessary steps to protect that investment.
For more information on how to Winterize Your Trees, see our website.