Nurture young trees through the drought
The continued heat and drought in South Texas are making it tough for landscapes to thrive. Even the trees are starting to show their distress.
Gardeners report that their trees and shrubs 2 years old or younger are wilting or losing leaves, even when watered on a regular basis with the sprinkler, by hand or with a drip line. There are a lot of interconnected issues in this problem.
Here’s a breakdown.
The young age of the tree.
With our shallow, rocky soils, it is not surprising that even recommended varieties of trees and shrubs take a relatively long time to get established and produce a significant root system. Chances are pretty good that a tree or shrub that has only been in the ground for two years or less is still relying on the roots in its root ball to collect and distribute the water and nutrients from the soil.
Watering the wrong area.
Because the only root system that exists is at the base of a young plant, irrigating the area under the outside crown edge puts water beyond the reach of the roots. Water has to be applied closer to the base of the tree.
Not watering enough.
Even if the young trees or shrubs are watered at the base where the root ball exists, the watering is often not adequate to penetrate and moisten even a small root system. Ten minutes of hand-watering twice a week at the base of newly planted small perennials may be enough for them, but it won’t be enough for a newly planted live oak tree. The typical 30-minute spray of the sprinkler may only penetrate 2 or 3 inches into the soil, nowhere near deep enough for a tree’s root ball.
On the radio show I do with horticulture specialist Jerry Parsons, “Milberger’s Gardening South TX” on 930 AM, I had been advocating using your fingers to dig into the soil over the root ball to make sure the soil is moist 2 to 3 inches down. But after more research and hearing from area gardeners, it is clear to me that the water needs to penetrate the whole depth of the root ball to provide enough water for young trees.
Parsons and fellow Express-news
gardening columnist Neil Sperry believe you’ll soak the root ball if you hand-water the problem plants every other day.
Mark Peterson, who also participates on my radio show, recommends watering newly planted trees and shrubs based on the trunk’s diameter: 1 to 2 gallons per inch of diameter three times per week.
For slightly older plantings, he suggests that same amount of water be applied to the root ball once per week so it penetrates 4 to 6 inches. He recommends poking into the soil with a screwdriver to determine how far the moisture penetrated.