Fort Worth is in the throes of a heat wave, with no rain for a month and drying winds, and a Texas tree group has advice on what we need to be doing for our trees.
According to the Texas Trees Foundation, a nonprofit tree planting organization dedicated to greening North Central Texas, you need to prioritize trees over other landscape plants, including lawns.
In times of drought and water restrictions, a lawn left unwatered can go dormant and turn brown without dying. Even if it does die, a lawn can be re-established in a single season.
A large tree cannot.
How to water
During a drought, a tree requires irrigation, with the goal of sustaining the tree, versus watering to make it grow.
Trees should be watered slowly and deeply. No sprinklers. Those are for lawns, not for trees. Use a bubbler, drip emitters, or a hand-held hose to deliver water to the tree’s root zone. Water the soil one to two feet deep each time you water and let the surface dry between waterings.
Deep watering encourages deep rooting — and deep roots are the best way for a tree to survive a drought.
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.
The dripline is the edge of the tree's branches outward. Don't water trees at the trunk. As a basic rule of thumb, apply water in a circular band that’s at least half as wide as the distance from the trunk to the dripline.
Time for a checklist:
- The best time for summer watering is in the morning or evening, from 7 pm to 8 am.
- Avoid watering during the hottest part of the day, 10 am-6 pm, since water will get lost in evaporation.
- Remove grass and excess plant competition from around any tree to decrease water stress. Many plants, including grass, 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 a 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.
Don't use fertilizer and don't prune your tree during summer months, since it can cause more stress. Fertilizers promote growth that the tree cannot sustain under unfavorable conditions, and pruning off leaves takes food away from an already stressed tree. The only pruning that should be done is to remove dead branches or any branches that pose a hazard.
Signs of distress
Drought is defined by a relatively long duration with substantially below-normal precipitation, usually occurring over a large area. During times of drought, a lack of moisture can cause trees to suffer from drought stress. 2022 marks the eighth driest year in Texas over the past 128 years.
One early sign of stress on a tree during drought is wilted leaves. Another sign is leaf scorching, when the edges of leaves or the space between a leaf’s veins turns brown.
When a tree begins to exhibit signs of drought stress, irrigation must begin immediately to avoid long-term damage to the tree. Drought and high temperatures deliver a one-two punch to trees. Trees exhale moisture from their leaves in a process called transpiration. As temperatures climb, transpiration kicks into overdrive. During a drought, there isn’t enough water in the soil to replenish the water lost. When this happens, trees adopt survival strategies that can stress and weaken them.
Established in 1982, the Texas Trees Foundation manages the nation’s largest nonprofit urban tree farm and plants trees on public property. If you are interested in a planting project in your community call 214-953-1184 or visit their website at www.texastrees.org.
Texas Trees Foundation’s Urban Forester Rachel McGregor says you should not ignore local water use restrictions. But ideally, you irrigate established trees once every two weeks during the growing season.
"Trees provide an enormous asset to our landscape by reducing heating and cooling cost in our homes, cleaning the air we breathe, increasing our mental and physical health, decreasing storm water runoff, and many other benefits," McGregor says.