Trees and shrubs can suffer desiccation injury during our windy, dry, cold winters. Even though trees are dormant over the winter, they are still alive and require water to survive, especially in windy weather. By providing some moisture during dry periods, you can keep your landscape trees healthy.
You might not see the damage from desiccation while it is occurring, but come spring and summer, evergreen trees will brown, and may not recover. Deciduous trees may fail to leaf out and may be dead by spring.
Newly planted trees are particularly vulnerable. The new tree needs time to establish an adequate root system, up to several years depending on the size. While that root establishment is occurring, a relatively small number of roots have to provide water for the trunk, canopy, and in the case of evergreens, needles or leaves.
If like last year, the winter brings almost no snowfall, plan to water the trees and shrubs in your landscape. The ground should not be frozen. Choose a day when it is 40 degrees and start as soon as it gets warm enough. Starting early will allow the water time to soak into the soil before the temperature drops at night. Apply water slowly inside the dripline of the tree, and beyond if possible. Soaker hoses, sprinklers, spray wands, and leaky-bag devices can all be used. You can also put some very small holes in the bottom of buckets to create leaky buckets to apply water slowly.
Established trees should be watered at least once a month, newly planted trees perhaps twice a month. Apply 10 gallons of water for each diameter inch of the tree at 6 inches above ground level.
It will help to mulch around the trees before winter arrives. Mulch reduces evaporative loss of moisture. Apply a 1- to 2-inch layer of mulch around the tree. Do not pile the mulch around the trunk. Wood-based mulches work, as do shredded leaves or grass clippings. Do not use aspen or cottonwood leaves for mulch, as they carry fungal disease.
Taking a little time this winter to take care of your trees and shrubs will pay big dividends in the spring.
El Paso County Extension is operating remotely due to COVID-19. Submit gardening questions by email at email@example.com.