Winter arrived with a vengeance this week in Boulder County! Snow once again covers the ground, and with temps below 0, and more snow in the near forecast, it will stick around for awhile.
Many people assume that if there is snow, there is moisture, but that is not really the case. The wonderful fluffy, powdery snow that is so popular at our ski slopes actually only contains about 5% moisture content. Spring snows contain up to 15%, with our average at just about 10%. That being said, many plants and trees require supplemental watering during extended dry periods. In particular, woody plants and trees with shallow root systems, and many evergreens benefit from additional watering. Birches, maples, lindens, alders, dogwoods, willows, and mountain ashes are all examples of plants and trees to keep an eye on. Evergreens include spruce, fir, arborvitae, yew, Oregon grape-holly, boxwood, and euonymus.
Mulch is also beneficial to retain moisture.
The result of long, dry periods during fall/winter is injury or death to parts of plant root systems. Affected plants may appear perfectly normal and resume growth in the spring using stored food energy. Plants may be weakened and all or parts may die in late spring or summer when temperatures rise. These weakened plants may also be subject to insect and disease problems.
Turf: water only when temperatures are above 40 degrees F. Apply water at mid-day so it will have time to soak in before possible freezing at night.
Trees: newly planted trees are most susceptible to winter drought injury. Trees generally take one year to establish for each inch of trunk diameter. Trees obtain water best when it is allowed to soak into the soil slowly, to a depth of 12.” Apply water to many locations under the dripline and beyond if possible.
Shrubs: For newly planted shrubs (under 1 year), apply 5 gallons two times per month. Small (< 3′) established shrubs should receive 5 gallons monthly, and large (>6′) established shrubs require 18 gallons monthly. Water within the dripline and around the base.
Much of this information was gathered from the Colorado State University Extension website:
For additional information, reference Planttalk Colorado at the above site.