Have you noticed all the dead or dying trees in our beloved Williamson County? Williamson County Extension Agent Taylor Reeder said there’s a reason for that.
“As plants are deprived of moisture, their roots and tissue begin to decline,” she said. “Even our more mature, established trees will suffer during a drought.”
So, what’s a homeowner to do to prevent dying trees? We’ll try to answer that question by describing when to water, how to water and where to water.
Everyone knows that newly planted trees need deep supplemental water during the first couple of years. But most of us do not think about our established trees. Oak, sycamore, maples, and evergreens such as Arborvitae and Leyland Cypress are very shallow rooted. Feeder roots in most trees are within the top 4 to 8 inches of soil. Couple this shallow depth of feeder roots with the drought Williamson County has been in since mid-June, and we witness the demise of our beloved trees!
Taylor recommends that homeowners invest in an inexpensive rain gauge so each of us may monitor rain in our own yards. Anytime Mother Nature fails to deliver a full inch per week, then supplemental water is essential. New trees need the supplemental water immediately, and weekly. Established trees need the supplemental water starting week three or four after Mother Nature fails to deliver, and weekly thereafter.
When in doubt, dig down about 6 inches near the canopy of the tree to scoop up a handful of soil. Just like Goldilocks, if it balls up but is moistly crumbly your moisture is “just right”. But if it dryly falls apart, then you will know your soil is too dry. Supplemental water is best done in the early evening as this provides your tree maximum time to take up the water without sunlight stress.
Irrigation systems rarely put out enough water to simulate Mother Nature’s 1 inch! Test your output by placing a shallow dish to catch the spray or soaker hose output and you’ll likely find you need to supplement further. A soaker hose or circular bubbler hose attachment is the best option.
Fewer deeper waterings are recommended. This means you’ll water once or twice per week for approximately 20-30 minutes per tree depending on the water flow. Short, more frequent watering will only encourage roots to come closer the surface which is not desirable for the long term health of your tree.
Tree roots always extend to the full circumference of the tree. Look up into the canopy. Place the hose to cover the full canopy of the tree. Never, never place a hose at the base of the tree trunk as this will result in trunk root rot.
Ultimately, if your plant succumbs to drought, you will need to replace it. When considering what to replace it with, remember a common phrase we like to use, "Right Plant, Right Place." Decide whether that plant will grow well in the area you wish to plant. Know what hardiness zones it will grow in, whether it prefers sun or shade, what its watering requirements are, and what its mature size will be. If you place plants properly, they will incur less stress, which will save you time and money in the future.
“We are (hopefully) coming out of our drought so will receive more help from Mother Nature during our winter months,” Reeder said. “I am hopeful our Williamson County homeowners will take timely action next year (if needed) to avoid further tree loss.”
For further information, search online for the UT Extension publications SP682 Watering Trees and SP615 Why Do Trees Die. Or contact the Williamson County Extension office diagnostic team at email@example.com for assistance with your horticulture concerns.