Saturday, October 27, 2018

Tips for Winter Watering

Colorado winters are unpredictable and it isn't unusual to have an extended dry period before the spring rains begin. Following are tips for winter watering of turf, trees and shrubs from Dr. James Feucht, CSU Cooperative Extension Landscape Plants Specialist.

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Colorado winters can be dry in more ways than one. During extended periods - particularly in January and February - when there may be little or no snow cover, the lack of soil moisture and atmospheric humidity can damage plant root systems unless they receive supplemental water. Affected plants may appear normal and resume growth in the spring, only to weaken or die in late spring or early summer because the amount of new growth produced is greater than the weakened root system can support. 

Most woody plants, which have shallow root systems, require supplemental watering during extended winter dry periods. Evergreen shrubs, particularly those growing near a house, may suffer root system damage during dry spells. Examples are plants such as Pfitzer and "Tammy" junipers.

Lawn grasses also are prone to winter damage. Newly established lawns, whether they are started with seed or sod, are especially susceptible to damage in dry weather. Pay particular attention to turf on south exposures.

Water during winter only when air temperature is above freezing. Apply water early in the day, so it will have time to soak in before nighttime freezing. If water stands around the base of a tree, it can freeze and damage the bark.

In most years, one or two winter waterings will be enough to keep plants from suffering winter damage. A soil needle (root feeder) attachment to the garden hose is recommended for applying water to young or recently planted trees and shrubs. For most junipers, about l8 inches is sufficient. With shallow-rooted trees, such as linden, maple and birch, 9-12 inches is correct. If a portion of a plant's root system is beneath a sidewalk or other obstructions, slant the soil needle to apply water beneath these surfaces.

When watering young trees, the most important area is halfway between the trunk and several feet beyond the "drip line" (the branch extremities). If water is applied through a soil needle in a zigzag pattern around the tree, all parts of the tree will receive enough. Leave the needle in the ground for one minute per spot, moving it every six to eight inches. For large, established trees, sprinklers are more efficient and the lawn can be watered at the same time.