Watering Trees and Shrubs: The Drip Line and Root Irrigators

The Drip Line

This is the circle on the soil beneath a tree's outermost branch tips—where rain drips from leaves. Water young trees up to and just beyond the drip line. As plants mature, roots extend farther beyond the canopy (wider in sandy soil). Water adequately by making a wider basin (flood irrigation) or moving sprinklers, soaker hoses, or drip emitters outward.

Using a Root Irrigator

The needlelike probe injects water into the root zone. Insert slowly at an angle so top soil gets wet. Don't go deeper than 1–1.5 ft or stay in one spot more than a few minutes. Work in concentric circles around the trunk, moving outward just past the drip line, using the injector every 3 ft.