Texas Trees Foundation says we should water our trees immediately

The Texas Trees Foundation says that trees should be given priority over all over landscaping, including lawns, because of the extreme heat. A lawn left unwatered will naturally go dormant for the season and turn brown, but can turn green again after rain or watering. A lawn is shallow; it can be re-established in a single season. A large tree cannot. Save the tree.

How to water your tree

• Do not water established trees at the trunk. Instead, water from the "dripline" - which is the edge of the tree’s branches and outward. The basic rule of thumb is to apply water in a circular band that’s at least half as wide as the distance from the trunk to the dripline.
• Trees prefer to be watered slowly and deeply. Sprinklers are for lawns but not for trees. Instead, use a bubbler, multiple drip emitters, or a hand-held hose to deliver water to the tree’s root zone. Water the soil to one to two feet deep each time you water and let the surface dry between waterings.
• The simplest method of watering: Turn your garden hose on a slow trickle and leave it in different zones within the dripline until you can easily insert a screwdriver into the soil. This kind of "deep watering" encourages deep rooting – and deep roots are the best way for a tree to survive a drought. Irrigate established trees once every two weeks during the growing season.

Other techniques

• The best time for summer watering is in the morning or evening between the hours of 7 pm-8 am. Avoid watering during the hottest part of the day (10 am-6 pm) because water gets lost in evaporation.
• Remove grass and other plants which can compete within the soil root zone for available water. This water competition can be severe.
• Use mulch to conserve water and prevent weed competition. Mulch is any tree’s best friend. Besides minimizing evaporation of soil moisture and limiting rainwater runoff, mulch also protects the tree from mower and weed trimmer damage. Wood chips and shredded bark can be used for mulch. Cover the area with mulch about 2 to 3 inches deep, taking care to avoid the area next to the tree’s trunk.

Do not use fertilizer or prune your tree during summer months. Both cause more stress. Fertilizers promote growth that the tree cannot sustain under unfavorable conditions and pruning off good leaves takes food away from an already stressed tree. The only pruning that should be allowed is to remove dead branches or any branches that pose a hazard.

Your trees will show signs if they are stressed from the heat:

• Wilted leaves are one of the early signs of stress on a tree during drought.
• Leaf scorching, when the edges of leaves or the space between a leaf’s veins turns brown

(CultureMap)