Prolonged periods of summer drought dry out the soil, stressing not only bluegrass lawns and wild stands of mountain pines, but also urban landscape trees. During these same periods of drought, water restrictions can make it more difficult for homeowners to keep their trees sufficiently watered.
“Adequately watering your trees is the best way to ensure optimum growth and vigor during the summer months,” said Keith Wood, community forestry program manager for the Colorado State Forest Service. “Dry trees become susceptible to root and branch die-back and subsequent insect and disease problems.”
The most recent U.S. Drought Monitor map, released last week, indicates that all of Colorado is currently experiencing some form of drought – with almost the entire state under “severe” or “extreme” drought classifications.
The CSFS offers the following tips to keep trees healthy without overly inflating the water bill:
• Water a wide area. Tree root systems, unlike carrots, may spread two to three times wider than the height of the tree, with most absorbing roots in the top foot of soil. Apply water to soak the entire area within the drip line (the critical root zone directly underneath the full span of a tree’s branches).
• Water slowly. To ensure deep penetration, use a deep root fork (inserted 8 inches or less), soaker hose on low setting or soft spray wand to apply water slowly to the full area within the drip line. Placing a running garden hose against the base of a tree for several minutes is far less effective.
• Keep the yard green. Trees located in irrigated lawns generally do not require additional water, as long as the area surrounding the tree receives adequate moisture. Conversely, a dry, yellow yard means the roots of any trees present are also dry.
• Focus on non-irrigated trees. Trees that do not receive water from sprinkler systems or irrigation require additional water. Every week, apply 10 gallons of water for each inch of tree trunk diameter. Water newly planted trees even more frequently; larger trees, which have extensive root systems, can be watered less frequently.
• Mulch. Mulch is an inexpensive solution 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 (removing any grass first, if necessary). Do not allow the mulch to directly contact the trunk.
• Follow the rules. When planning a watering regimen, remember to follow any current watering restrictions.
Visit www.csfs.colostate.edu for more tips on tree watering, planting and general care.