Trees can be the most valuable asset in your home’s landscape. They add resale value to your home and can reduce heating and cooling expenses. Watering trees is worth talking about because it is different than you might think. Trees do need supplemental irrigation and need to be watered differently than the lawn.
Tree roots are opportunistic and the largest number of roots will be in the location that is most likely to receive rain or irrigation. In most situations, this means roots will be at the dripline, which is out at the edge of where the tree canopy or branches end. Think about where most of the rain will fall when the tree is covered with leaves. Watering right next to the trunk or spraying the leaves of the tree is not as beneficial as watering where natural rainfall would be, a few inches inside and beyond the dripline.
An efficient way to water is by using a soaker hose or drip irrigation. These methods lose very little water to evaporation. Sprinklers work as well, but will need to be adjusted to sufficiently water a tree deeply as compared to watering a lawn. Also, laying down a water hose and letting it slowly run works great, but you will need to move it around the tree periodically to ensure that all areas get sufficient moisture.
In order to create a healthy root system, trees should be watered deeply and infrequently. When watering, put down an inch of water at a time or ensure that you have watered to a depth of between 6 to 10 inches. This may sound difficult, but it’s actually very simple to make sure you are getting enough water to your trees. After watering, stick a screwdriver or a shovel into the ground. In most of our soils, it will only go easily in when the soil is moist. (Pushing the screwdriver into the ground via one of the gigantic cracks in our soil does not count!) If you are using a sprinkler, put out rain gauges or catch cans (use tuna cans) and measure one inch of water being applied.
How often should you water? If we are not receiving adequate rainfall, established trees need a deep watering twice a month. Also, you can check the soil with your screwdriver and if it does not easily go in 6 inches, it’s time to water again. New trees need to be watered more frequently for the first three years of their life as they become established.
Janet Laminack, County Extension Agent-Horticulture, Texas A&M AgriLife Extension – Denton County, firstname.lastname@example.org, (940) 349-2883 or Metro (972) 434-8812