University of Maryland Extension

Watering Guidelines


Back to Trees/Shrubs - Post Planting Care

Plants less than two years old should be watered deeply once or twice per week during the hottest and driest part of the summer.  This encourages roots to grow deeper. More frequent, light watering only wets the surface promoting a shallow root system. Also, mulch to conserve soil moisture.  


Water plants according to their needs. Watering depends on the type of plant, soil texture, and weather conditions. Some plants tolerate dry conditions better than others. Sandy soils dry out faster than heavy soils or those well supplied with organic matter.

Extended periods of drought can negatively affect most plants. Set priorities! Water trees, then shrubs, then herbaceous plants. Water first what you least can afford to lose.

Check your soil several inches deep and water whenever dry. Avoid watering during the heat of the day when a lot of the water is lost to evaporation.

Watering is not just a summer chore. Trees and shrubs, especially evergreens, can suffer from winter drought damage. Keep an eye on weather conditions in the fall and winter and if rain is severely deficient, water your landscape evergreens. This is not an uncommon situation September through November. Water when the ground is not frozen and temperatures are above 40 degrees F.


Water only the landscape. Avoid setting sprinklers where water ends up on your sidewalks and driveways. Apply water over as much of the root area of your plants as possible. For example, the root system of a large tree extends outward well beyond the drip line. Applying water just around the tree trunk does little good.


Apply water overhead with sprinklers or hoses, or apply water directly to the soil with soaker hoses and drip irrigation. Overhead sprinklers apply water rapidly to a patterned area. However, overhead watering can increase disease problems especially if water sits on the leaves for a prolonged period of time. Sprinklers can be portable and moved around the landscape as needed, or they can be permanently installed systems. Uniformity of watering depends on the type of sprinklers used,water pressure, and wind conditions. Closely monitor watering patterns with sprinkler use and make sure all parts of the landscape receive adequate water.

Soaker or Drip systems apply water slowly at ground level. The advantages of these systems are: they apply water where it's needed, they apply water under plant foliage which reduces evaporation, they keep leaves dry reducing the incidence of foliar plant diseases, and they use less water.

With either system, check on the effectiveness by examining the soil for moisture. After watering, check several locations in the landscape with a hand trowel or spade to make certain the soil is moist down six inches or more.

Additional Resource

Publication: (PDF)  HG 85 Watering Tips for Drought Conditions

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