Dry, sunny, warm and windy winter conditions have left many Colorado landscape plants short of moisture, and Colorado State University Extension specialists recommend supplemental watering to prevent root damage and promote healthier spring growth.

Evergreens, newly planted trees and shrubs, grasses, and plants in exposed or south-facing sites face the highest risk from winter drought, according to a CSU news release, which can lead to needle or branch dieback and greater vulnerability to pests and diseases.

Plants continue root growth, nutrient transport and photosynthesis — especially in evergreens — even during dormancy, according to CSU Extension guidelines. Prolonged dry periods without sufficient soil moisture cause accumulating stress that impacts long-term plant health.

Extension specialists advise watering only when air temperatures exceed 40 degrees and the soil is unfrozen. Frozen ground blocks absorption, leading to runoff with no benefit to plants, and watering should be avoided over snow cover.

Occasional deep watering — typically one to two times per month during extended dry spells — is more effective than frequent light applications, CSU Extension notes. Newly planted trees and shrubs, along with evergreens, benefit most.

Young trees require about 10 gallons per inch of trunk diameter at the base — for example, 20 gallons for a 2-inch trunk — applied near the base or out toward the dripline. Mature trees need water at and beyond the canopy edge to cover the full root zone, with enough volume to wet the soil to roughly 12 inches deep. Shrubs generally need 5 to 18 gallons per application, depending on size.

Many native plants and low moisture-adapted landscapes require little or no supplemental winter water. Established perennials and drought-tolerant species also need less frequent irrigation, according to CSU.

Use a hose equipped with a sprinkler or soaker hose for winter applications rather than turning on automatic irrigation systems, which risk damage from freezing pipes until spring thaw. Detach and fully drain hoses after each use to prevent pipe bursts.

Winter watering is the most practical step homeowners can take to protect plants in Colorado’s arid winter climate.

For detailed guidance, see the CSU Extension fact sheet on fall and winter watering.