GARDENING: Watering mature trees

By Sara Moran, County Extension Agent

Horticulture for Midland and Ector counties

Water is crucial to keep our landscapes alive. During drought, providing efficient irrigation to our trees will contribute to trees’ health and overall well-being, minimizing the incidence of insects or diseases. The information provided below applies to mature trees. Newly transplanted trees (below two years) will have different requirements in some instances mentioned above. Here are some guidelines to help you water your mature trees effectively:

1. Assess the watering needs. Determine the water requirements based on the tree species, season of the year, and soil conditions. Native trees generally require less watering compared to non-native species.

2. Water deeply and infrequently. Instead of frequent shallow watering, it’s better to water deeply and less often. This encourages the development of stronger roots, making the tree more resilient to drought conditions. Apply water slowly to allow it to penetrate the soil deeply.

3. Water at and beyond the dripline. Mature trees have established root systems that extend far beyond their canopy. The dripline is an imaginary circle in the ground that surrounds the outer edges of the tree’s canopy. Most feeder roots (root hairs) are located at and beyond the dripline. Feeder roots seek, absorb, and transport water and nutrients to the tree. Therefore, we should water the tree evenly within this zone, extending slightly beyond the dripline to ensure adequate coverage.

4. Choose the right time. Water your mature trees in the early morning or late afternoon when temperatures are cooler, reducing water loss due to evaporation. Avoid watering during the hottest part of the day when evaporation rates are high. The goal is that most of the water stays in the ground to be accessible to trees.

5. Use proper irrigation techniques. You can use several methods to water mature trees effectively. These include soaker hoses, drip irrigation systems, or using a slow-release watering bag or bucket. Avoid high-pressure sprayers or sprinklers, as they may not deliver water efficiently to the root zone. Check your soil moisture to ensure water is going deep in the soil.

6. Monitor soil moisture. Regularly check the soil moisture around your mature trees. Insert a screwdriver or soil moisture probe into the soil to determine whether it’s dry or moist. Water when the soil is dry to a depth of 2-4 inches. Recently transplanted trees might require water more often since their root system is not established.

7. Mulch around the base. Apply a layer of organic mulch around the tree’s base, such as wood chips or bark. Mulch helps retain moisture, regulates soil temperature, and reduces weed growth. Keep mulch 3-4 inches away from the trunk to prevent moisture buildup and potential rot.

8. Adjust watering based on weather conditions. Modify your watering schedule during periods of rain or drought. If there’s ample rainfall, reduce or stop supplemental watering temporarily. In dry periods, increase the frequency and duration of watering as needed. Check your soil to determine if water is required.

Remember that the watering needs of trees can vary depending on their species, climate, and other factors. If you have any questions, it’s best to consult with a local arborist or horticulturist who can provide more personalized guidance. You can also contact your Texas A&M County Extension Office in Midland (432-686-4700) and Ector (432-498-4071) counties; or send an email to [email protected]. Happy Gardening!