Winter Watering for Trees and Shrubs in the Mountains

Coming out of a challenging 2018 filled with record high temperatures and severe to extreme drought designations through most of Colorado, we are all thinking about our yards, gardens, trees and shrubs for 2019. Although many areas have received some precipitation over the past couple of months, recovering from a drought takes time, and we need to work towards tending to our drought-stressed landscapes in order to set ourselves up for a successful 2019 season.

Supplemental watering in the winter is a reality for Coloradans, especially in the Mountains, where the air is drier. Most trees have shallow roots, found in the first 18 inches of the soil. These sub-surface roots are vulnerable to dry conditions, and require supplemental watering in particularly hot and dry seasons. A drought-affected landscape has depleted its subsurface soil moisture content, requiring extra care in the fall to restore soil moisture for plants. Fall and winter care is critical in restoring that soil moisture that plants will rely on, going into the following growing season.

Supplemental watering in the fall and winter are an important aspect of caring for a Colorado landscape in drought-affected areas. A combination of dry conditions, higher elevation, wind, increased sun intensity, and limited moisture make winter watering a critical component of Colorado gardening.

CSU Extension recommends watering within the drip-line (the soil area from the trunk to the outer edges of the branches, similar to the ‘footprint’ of a tree or shrub) to a depth of around 12 inches once or twice a month from October through March. You can use several different methods to water, including soaker hoses, soil needles, and spray nozzles/wands. Younger trees and new plantings require more watering than established landscape trees and shrubs.

Watering should take place in dry winters with no snow cover. It is important to only water your landscape plants when daytime temperatures are above 40 F, and if the ground is not frozen. Restrict watering to mid-morning, allowing time for the water to percolate to the roots, before the possibility of an overnight freeze. In addition, apply 2-4 Inches of mulch (leaving 6 inches from the base of the trunk), as mulching provides insulation and helps to conserve moisture in the soil.