The Best Way to Water Shrubs

Irrigation System

• Target the soil around your shrubs with a garden hose or a trickle or drip irrigation system. If using a hose, a soaker hose is best because it delivers an even application of water at low pressure. Using these watering methods ensures that water reaches the roots, where it's needed. On the other hand, turning on overhead irrigation such as a sprinkler system causes the water to cover foliage first, and this can lead to the development of fungus and leaf spot diseases, among other problems.

Thorough Soaking

• Water thoroughly rather than frequently. When shrubs are young, this encourages them to develop deep root systems, which are stronger and healthier than shallow roots prone to dryness from topsoil water evaporation. Later, watering deeply ensures that the entire root area is soaked so that none of the roots shrivels and dies from dehydration. Typically, applying 1 to 2 inches of water once a week should suffice for shrubs.

Time of Day

• Watering at the correct time of day is essential for shrubs' health. Early morning is best, before winds whisk water from the topsoil and before temperatures rise to cause rapid evaporation of water. Alternatively, you can water in the late afternoon, as the heat of the day is dissipating. In this case, make sure you leave a few hours of daylight to allow water on foliage to dry before nightfall; otherwise, you risk fungal disease developing on wet leaves overnight. With soaker hoses and similar methods of irrigation, wet foliage is not as much of a problem, allowing you to water in the evening when necessary.

Quick Tips

• Keep in mind that the roots that absorb water are not close to the trunks of shrubs; instead, they're several inches or even feet out from them. To make sure the entire root system is being watered -- especially to a depth of 12 to 18 inches, which is as far down as most shrub roots go -- dig a small hole to look or push a tensiometer probe into the soil; a reading of 5 to 15 centibars 12 to 24 hours after watering indicates adequate watering. You can also tell your shrubs are dehydrated when leaves turn yellow or brown and drop or you notice crispy spots from leaf scorch. Keep in mind, however, that similar conditions can also develop from overwatering, which rots roots and prevents them from taking up water, dehydrating their shrubs in the long run.