Winter weeds masquerading as your lawn

Don’t waste water and time trying to rescue rescuegrass.

It’s official: rescuegrass has started going to seed. Among the spring weeds in yards and roadsides for the past couple of months, this is the one that looks like lush turf grass, but with flat oat-like seedheads. It’s a shallow-rooted (and invasive) cool-season grass weed, widely dispersed in lawns and Texas pastures.

Rescue grass lives fast, dies young, and grows back from seed every winter. Thanks to the relatively mild temperatures during its growing season, it can be the one of the greenest grasses of the year in south central Texas. And it may stand out like a sore thumb in a dormant Bermuda grass lawn.

Now that it’s April and the days are getting warmer, rescue grass is nearing the end of its short lifespan, turning yellow or brown and shedding lots of seedheads. The sudden stubble of dying rescue grass may make your yard look like it’s in big trouble. But don’t be fooled into watering to bring it back (or applying weed and seed fertilizer to kill it.)

Like other cool-season weeds, it’s already finishing up and going to seed so just take a deep breath and remember to wait a little bit. If you look closely, you’ll start to see that summer turf is gradually starting to replace it. Because its cool growing season barely overlaps with warm-season Bermuda grass, St. Augustine, and zoysia, rescue grass is exiting stage left just as your summer turf is entering.

If you need quick relief from the seedy appearance of withering rescue grass, just mowing it is all you need to do at this point. (In mulched flowerbeds, it can be easily pulled.)

Here’s a few common questions that arise when you spot your winter grass competing with April temperatures.

Why does this matter?

Many homeowners are so horrified by the seedy appearance of rescue grass that they start watering heavily in April. But watering rescue grass is a waste of effort and water. Soon it’ll be completely replaced by warm-season grasses like Bermuda grass, St. Augustine, and zoysia.

With the Edwards Aquifer low and Stage 2 restrictions continuing for the foreseeable future, it’s not a good idea to waste water on weeds.

How can I tell if my dying grass is just rescue grass?

One of the easiest clues is its behavior, growing lushly during the wrong season, and suffering just as the temperatures warm up. The flattened spikelet seeds are also distinctive, with four to nine layers each. In addition, the leaf sheaths are noticeably “hairy.” (The upper surface of leaf blades may be fuzzy as well.) Since they’re so shallow-rooted, clumps pull out easily from the ground.

Should I spray it with herbicide?

It’s too late. As I mentioned previously, rescue grass is already dying. A common mistake some homeowners make is to spray all the weeds in spring, which can cause lasting damage to your summer turf.

The only herbicide semi-effective for rescue grass might be a pre-emergent granular application, but only if applied around Labor Day. The downside: it would also suppress wildflowers and other beneficial plants.

The simplest solution is to just keep mowing. Rescue grass will fade out over the next month, and the quicker it warms up, the sooner it will die. For now, your mower is probably the most effective way to send it on its way.

Brad Wier
Brad Wier
Brad Wier is a SAWS conservation planner. Years in South Texas landscaping and public horticulture gave him a lasting enthusiasm for native plants that don’t die when sprinklers -- and gardeners -- break down. He’d rather save time and water for kayaking and tubing. He is a former kilt model, and hears hummingbirds.
Ask the Garden Geeks

Have questions, insights, or exciting news to share? Our resident expert Garden Geeks are here to help!