Winter watering of trees and shrubs will be beneficial if warm winter temperatures and lack of precipitation continue. The priority for winter watering is young plants first which includes those planted in the past year and especially those planted in the fall. The second most important are evergreens, mainly those growing in exposed locations and near the south sides of buildings.
Do not water trees and shrubs when the soil is frozen or the air temperature is below 40 degrees Fahrenheit. Watering early enough in the day for moisture to soak into the soil will prevent ice formation over and around plants overnight. Water just enough to moisten the soil 6-8 inches deep. Watering once or twice during winter will be adequate. If conditions remain warm and dry through winter into spring, it will be important to begin watering as soon as the soil thaws this spring.