From the Colorado State Forest Service via The Sterling Journal-Advocate (Jeff Rice):
Despite a relatively small amount of precipitation falling recently, the most recent U.S. Drought Monitor map indicates that nearly all of Colorado is currently experiencing some level of drought. Trees in urban and community settings throughout this region are dormant now, but still require occasional watering during dry winters to remain in top health.
Keith Wood, urban and community forestry manager for the Colorado State Forest Service, says planted trees in Colorado, especially at lower elevations, often require additional watering in the winter months during extended dry periods (e.g., more than two weeks without lasting snow cover).
“Adequately watering your trees is the best way to ensure optimum health and vigor that will carry through to the growing season,” said Wood. “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’s warm. The best time for winter watering is on days when snow has melted off and the temperature is above 40 degrees.
• Water a wide area. Tree root systems may spread much wider than the height of the tree, with most absorbing roots in the top foot of soil. 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 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.
• 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 abundant spring precipitation arrives, be sure to continue watering every few weeks in the absence of snow and colder temperatures.
For more information about urban tree care, visit the Colorado State Forest Service website at http://www.csfs.colostate.edu.