Get It Growing for 11/01/24

Mature trees have many benefits. They provide habitat for wildlife, offer shade and enhance the aesthetics of our landscapes. They’re even known to significantly boost property values.

As big and strong as those trees may look, they can still suffer during extended dry periods. Drought can take a slow — but serious — toll on tree health. And while we usually think of drought as a summertime phenomenon, this weather pattern can occur any time of year. In Louisiana, October and November are typically our driest months.

Unfortunately, Louisiana hasn’t seen much rainfall lately, and the U.S. Drought Monitor indicates that large swaths of our state are currently in a drought. If you have trees on your property, you can help them through this time by providing supplemental irrigation. This will help promote a healthy new canopy in the spring and safeguard the trees’ long-term well-being.

Perhaps because of their towering stature and sturdy appearance, it can be easy to think trees can take care of themselves, that they’ll get along just fine without any special treatment. Trees are plants, though, and just like all other plants, they need plenty of water to flourish. Now is the time to water your trees, especially if you haven’t done so in the past few years.

What happens if you don’t provide water during a lengthy dry spell? Drought-stressed trees may experience reduced growth, leaf damage and loss, branch dieback and even internal cracking and loss of larger limbs. Trees that endure repeated droughts will show more damage over time. While the extent of damage varies with drought severity, the bottom line is that drought weakens trees — leaving them more vulnerable to pests and diseases.

To find out if your trees need water and to test for soil dryness, push a long screwdriver or a knife into the ground. If the blade doesn’t slip into the ground easily, you need to water.

You also can look around the landscape for indicator plants that may hint at the need for water. Established evergreen azaleas, for instance, are pretty tough. When you see a mature azalea wilt in Louisiana during a dry period, it’s a good sign that your landscape is thirsty. (Side note: Just as we tend to forget about watering trees, we also sometimes leave large foundation plantings such as azalea, camellia and holly shrubs to their own devices. Be sure to water them as well.)

Mature trees do their best when they get about 1 inch of rainfall per week — or an equivalent amount provided via irrigation. LSU AgCenter experts recommend watering trees four to six times per year when rainfall is scarce. At the very least, you should water trees whenever a dry spell sets in.

You’ll want to use a slow, deep watering technique to quench your trees’ thirst. To do this, you can use either a soaker hose or a traditional garden hose.

A soaker hose drips water along its entire length. Lay it out under the tree canopy and let the water run slowly for 24 to 72 hours depending on the severity of the drought.

With a regular garden hose, turn the faucet on so there is a slow, steady drip or trickle. Place it under the tree and let it run for six to 10 hours. Then, move the hose to another location and repeat the process. Water in at least three to four locations, letting the hose run for several hours in each spot, to irrigate as much of the rootzone as you can.

If you see water running off and not soaking into the ground, turn down the faucet to slow the flow of water. This will allow the water to soak in better.

Be sure to water away from the tree trunk to reach the tree’s absorbing roots. Place your hose at least halfway between the trunk and the dripline, which is the imaginary line from the farthest edge of the tree canopy to the ground. For even better results, you can also water at or just beyond the dripline in the zone where the tree’s root system is actively expanding.

You also should consider mulching around your trees if you haven’t already. Mulch will help retain moisture and moderate soil temperatures, further protecting your trees’ health during a drought.

Trees provide many benefits, including adding aesthetic appeal to the landscape and playing an important role in the ecosystem. Photo by Randy LaBauve/LSU AgCenter

Trees can suffer in prolonged droughts. It’s important to provide water during these times. Photo by Randy LaBauve/LSU AgCenter

Water trees using either a soaker hose or a traditional garden hose running on a slow trickle. Photo by Randy LaBauve/LSU AgCenter

Place the hose away from the tree trunk when watering. To reach the actively expanding portion of a tree’s root system, water at or just beyond the dripline. Photo by Randy LaBauve/LSU AgCenter