How to take care of your North Texas lawn and landscape in summer heat

I’m not sure whether it’s those of us who garden here in North Texas or the plants we strive to grow that get hit the hardest by sudden changes to near-record high temperatures. Either way, it’s not a pleasant experience, so let’s point out some of the early warning signs of potential problems.

▪ Plants are wilting even though the soil is still very moist or even wet. There are a couple of possible causes here. Either the plants can’t pull water through their systems rapidly enough to meet the demands of their vigorous top growth, or the soils may be staying too wet (water-logged) for too long, crowding out the oxygen that’s needed for healthy roots. Effectively, the plants might have drowned. That can become very evident very rapidly when temperatures climb right after sustained rains.

▪ Lawngrasses suddenly turning yellow. This is most intended for gardeners who have seeded new lawns in tall fescue or who have over-seeded warm-season grasses, notably bermudagrass, with winter rye. The cool-season grasses go downhill very rapidly as summer approaches. If you have a warm-season grass such as St. Augustine or zoysia that is yellowing, that could be the fungal disease take all root rot. You’ve read about that here before.

▪ Magnolias, hollies, and other select evergreens dropping big batches of leaves. This is absolutely normal. It’s their time to exchange last year’s leaves for vigorous new foliage for 2025. Apply an all-nitrogen lawn food and water the root zone deeply.

▪ Older leaves of fast-growing trees turning yellow and dropping. You won’t see this right away, but when it turns hot and dry for good, look for leaves of mulberries, cottonwoods, silver maples, catalpas, and a host of other large-leafed trees to start turning yellow and dropping to the ground. It will always begin with the oldest leaves — those farthest from the growing tips to start turning first. They can’t pull water through fast enough to meet the promise of early spring cool, moist weather once summer arrives in full force.

▪ Nutsedge is popping up all over the lawn, landscape, and garden. Also known more commonly as “nutgrass,” this obnoxious weed loves the heat. It does most of its growing now through mid-fall. You can recognize nutsedge by the fact that all true sedges have triangular stems when you roll them between your thumb and index finger. Nutsedge grows as single plants that soon multiply into dense communities. Your best controls will be Image for Nutsedge Control and a somewhat more commercially used product called Sedgehammer. Both are widely available, but be sure you buy the Image product that is specifically labeled for nutsedge. Read and follow label directions carefully. And be patient!

▪ Newly planted trees and shrubs are wilting, even though you’re running the sprinklers more often than usual. Sprinkler irrigation alone will not be adequate for first-year trees and shrubs from the nursery. To explain: They have been produced in potting soils that are highly organic and lightweight (for purposes of minimizing cost of freight). Those soils dry out much more rapidly than your native soils adjacent to them once they are planted into your gardens.

New plants should be watered by hand using a water breaker or a water bubbler on a water wand handle. Apply as much water as the size of the container from which it was planted originally (a 10 gallon plant gets 10 gallons of water, etc.) and apply it every couple of days when temperatures exceed 95.

▪ Soil is drying out rapidly and flower and vegetable gardens are suffering accordingly. When temperatures climb and the sun hits bare soil, it will dry out rapidly. That’s the time that high quality mulches can really pay off. Well-rotted compost, finely ground pine bark, or other mulch that covers the ground with a 1-inch layer of organic matter will perform several important functions. It will reduce weed growth, lessen splashing and erosion, and moderate soil temperature fluctuations, as well as conserving moisture. Those are all good for your plants.

▪ New trees’ trunks are basking in afternoon sun. This probably isn’t a problem — yet. But it could be within a few months. Summer sun scald can ruin trees as it causes bark to crack and peel away. Internal tissues are exposed in the process. Apply paper tree wrap from the ground up to the lowest limbs to provide protection. Leave it in place for the first two years.

▪ Parts of your landscape seem dry even though the sprinkler system just ran overnight. You have broken or misaligned heads or a valve that isn’t functioning. You need to put your entire system through an irrigation audit. Hire a licensed irrigation contractor to do this for you. Have them run every station on each controller to be sure all heads are properly aligned and functioning correctly. Have them set the clocks to run according to your community’s restrictions. Ideally, have them install a “smart” controller. It will pay for itself in short order.

▪ Plant new grass seed soon. It’s a lot easier now than it will be 15 or 20 degrees from now. Be sure, too, that the new seedlings will have full or nearly full sun. I’ve written about how trees’ shade can cause loss of big areas of St. Augustine and bermuda. Don’t repeat those mistakes again here.