Don’t let occasional rains keep you from watering your trees this summer. Central Texas is still in deep drought. Stress from drought and heat can cause limb die back, increase vulnerability to insects and disease and contribute to tree decline. Apply 10-20 gallons of water once a week to trees planted in the last three years (unless it has rained at least one inch that week). Apply the water in a manner that allows it to soak in, not run off. Established trees need water too; spring winds have increased water loss from evapotranspiration (moisture loss from soil evaporation and leaf transpiration). For established trees, apply water in a doughnut-shaped area from inside the canopy to just beyond the drip-line. Water use restrictions are in effect for Austin, but you can still hand-water your trees any time. Applying mulch will help the soil retain moisture and insulate roots from the heat. Below are links to several resources about how to effectively water and mulch your trees.
Fast & Easy Hand Watering Tips
Supplemental Watering of Trees During Drought
Earthwise Guide to Tree Care During Drought
Effects of Drought Stress on Trees and Landscape Plants
Grow Green Mulching Video