Despite snow falling in many regions of Colorado recently, most of the state is still experiencing drought conditions after an abnormally dry period at the end of last year, according to the National Drought Mitigation Center. Trees in urban and community settings are dormant now, but still require occasional watering during winter to remain in top health.

Dana Coelho, Urban and Community Forestry Program Manager for the Colorado State Forest Service, said both established and newly planted trees in Colorado – especially at lower elevations – often require watering in the winter months during extended dry periods (i.e., more than two weeks without lasting snow cover).

“Watering your trees now during winter is the best way to ensure optimum health and vigor for the growing season in the coming spring,” Coelho said. “Overly dry trees become susceptible to root and branch die-back, and subsequent insect and disease problems.”

The CSFS offers the following winter watering tips: 

• Water when it is warm. The best time for winter watering is on days when snow has melted and the temperature is above 40 degrees.
• Water a wide area. Tree root systems may spread much wider than the height of the tree and the spread of the crown, with most absorbing roots in the top foot of soil and often far from the trunk. Apply water to soak the entire area underneath the full span of a tree’s branches.
• Water slowly. To ensure deep penetration, use a drip or soaker hose on a low setting (or soft spray wand) to apply water slowly to the full area at the rate of 10 gallons per inch of tree diameter. That equates to about 40 minutes of watering with a soaker hose for a young tree with a trunk 2 inches in diameter and 120 minutes for a more mature tree with a trunk diameter of 6 inches.
• Retain mulch. To retain soil moisture and save water, apply 4 inches of organic mulch onto bare soil within 2 to 3 feet from the base of the trunk, but not directly against the trunk.
• Repeat as necessary. Until spring precipitation arrives, be sure to continue watering every few weeks during periods of warm temperatures when there is no snow on the ground.

For more information about tree care in communities, visit the CSFS website at csfs.colostate.edu/colorado-trees/selecting-planting-and-caring-for-trees