Texas turf: Lawn grasses compete with bluebonnets; avoid 'deer wars' - San Antonio Express-News

Q: I'm concerned about my backyard. The photo with the tennis ball is St. Augustine ("carpet grass"), while the other photo is of a mix of St. Augustine and Bermuda. Runners on much of the lawn pull up easily. I'm worried that the lawn is dead. I have bluebonnets and other wildflowers in this area, so I'm concerned about bringing sod and topsoil in until we get spring rains.

A: Lots of thoughts are running through my head. Turf grass and wildflowers are not compatible. The wildflowers compete for space, to say nothing about water and nutrients, with the lawn grasses. They're especially challenging when new grass is trying to get started.

The biggest issue is in leaving the wildflowers unmowed long enough that their seeds can mature in May and June. By then, the turf grass will have grown far too tall and weak. When you finally do mow it, you'll probably kill a good bit of it. Wildflowers need to be grown in dedicated spaces where they won't have to compete.

St. Augustine and bermuda grass is shown, with some living St. Augustine denoted by its plump, green runners.

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As for whether the lawn grasses are dead or alive, your photo that includes both types of grass has some living St. Augustine in the lower part of the photograph. You can see its plump, green runners. If runners of either grass are dried and brown, they are dead. However, Bermuda (and to a lesser extent St. Augustine) has enough runners and rhizomes that it will green back up again with warmer conditions and spring rains.

This shows a heavy population of annual bluegrass (Poa annua).

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Your photo with all the green grass shows a heavy population of annual bluegrass (Poa annua) and probably rescuegrass or other grassy winter weeds. There is no control for those at this point. They will die out as it turns hot in six to eight weeks. However, you can prevent them, or at least reduce their populations greatly, by using pre-emergent weedkiller granules between Aug. 25 and Sept. 5.

Q: I have a long bed in which I have raised lantanas and rosemary. They have done very well, but I'd like to have a low evergreen shrub to go with them. It must be deer-proof, as we have hundreds of them in our area. What would you suggest?

A: No one can help you better than a veteran gardener of the deer wars. Forrest Appleton retired as a Texas Certified Nursery Professional. As a Bexar County Master Gardener (in one of the centers of the state's deer population), he prepared an outstanding list of the best deer-resistant plants. You can see it at https://aggie-horticulture.tamu.edu/plantanswers/publications/deerbest.html.

Some of the more popular evergreen shrubs he includes are Japanese boxwood, yaupon hollies (all types), nandinas (all types) and ceniza, or Texas sage. He also lists rosemary, gray and green santolina, trailing rosemary (where it's winter-hardy), wedelia and many others.

Primrose jasmine has turned brown since the December 2022 cold spell.

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Q: We have about 20 of these primrose jasmine plants (see photo) on our 1.3-acre lot. They're about 20 years old. They've done really well all that time, but since the Christmas cold spell, they have turned brown. I don't know if they have died back. What should I do?

A: I'm surprised they weren't hurt by the cold of February 2021. It was, overall, even worse than the spell this year. It's been a tough run to be sure. Bend a few of the twigs. If they're dry and brittle already, that means that portion of the plant is dead and could be removed. Keep clipping as far back as you must. They will almost assuredly sprout out again in March and April.

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Q: I've had an ongoing problem with onion grass in my flowerbeds. It smells like onions when I pull it, and it has the little white onions deep in the soil. But pulling it doesn't do much good, and mulching barely slows it down. So far, I've used bark mulch and cardboard boxes, but once the cardboard disintegrated, the onions came back. What can I do?

A: Broadleafed weedkiller products containing 2,4-D are usually labeled for control of wild onions. (Note that while the leaves look like grass, the plants are not members of the grass family. Their flowers are not at all the same.) Spray carefully so that your herbicide only goes onto the leaves of the wild onions, not saturating the soil and not drifting onto adjacent desirable plants. You may have to spray two or three times, and you always want to do so when the weeds are growing most actively.

As for using cardboard, its effectiveness is vastly overstated. It decays quickly on moist ground, and then the weeds regrow right through it. Commercial weed-mulching fabrics from a hardware store or nursery would be much better.

Q: When and with what should I feed my Nellie R. Stevens hollies to get the quickest possible growth?

A: Use a high-quality, all-nitrogen lawn food (no weed killer added) that has upward of half of its nitrogen in slow-release formulation. Apply it as new growth is beginning in March and repeat every eight or 10 weeks into early fall. Deep waterings on regular intervals is even more important for new plants. Water them deeply by hand with 10 to 20 gallons of water every two to three days from April through October and as needed thereafter.

Email questions for Neil Sperry to SAENgardenQA@sperrygardens.com.

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