St. Augustine stronger than Bermuda if conditions are good

By Neil Sperry | Published Wednesday, August 9, 2017

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Dear Neil: This spring I reseeded my lawn with Bermuda grass over St. Augustine. Now the Bermuda has taken over one-fourth of my lawn. Will it eventually overtake all of the St. Augustine?

Honestly, I’m amazed that you got tiny Bermuda seeds to sprout and grow in an existing lawn. The competition is usually way too fierce for the very small seedlings to survive. And, having said that, if you take fairly good care of your lawn, St. Augustine is almost always the predominating grass. Perhaps you run your lawn a little drier than the St. Augustine prefers.

Dear Neil: We planted a young cottonwood tree this spring. Its lower leaves are yellowing. Has it had too much water?

That is extremely unlikely. Cottonwoods can grow at water’s edge, which means that their roots can exist with a very high water table. It’s far more likely that it got too dry one or more times. It’s also possible, if you dug and transplanted it, that it is suffering transplant shock from loss of roots. Keep watering it.

Dear Neil: I have insects on my crape myrtles and okra that run around to the opposite side of the stem when I approach. I’ve tried sprays to kill them but they fly away. What can I use to get rid of them?

Those are probably some type of leafhoppers, and they really present no threat to you or your plants. I have them on my plants as well and I rather enjoy watching their antics.

Dear Neil: We have noticed for the past couple of years that after we mow our St. Augustine there are runners that are on top of the lawn. They’re still attached to the ground at their bases, but they’re not firmly rooted along the runners. Are we mowing too short, or is the soil too tight? The lawn looks fine otherwise.

This happens to most St. Augustine lawns in early or mid-summer. The roots on those runners are shortened and black, and I guess that suggests there might be some type of disease organism. However, it’s quite harmless. I just lift the runners with my shoe and mow them off. Within a few weeks it stops for the rest of that growing season.

Dear Neil: I am seeing bark on my large tree (not sure of type) that is shedding and falling. What can I do to save the tree, or should I remove it and move on?

You have a very large red oak, and it looks like it is suffering from Hypoxylon canker. That’s a fungus that moves into red oaks that are under stress following severe drought. We saw a great deal of it after the drought of 2011. I’ve been receiving fewer questions about it recently, but yours is not the only one. You should get a certified arborist on site immediately. It’s not an easy situation to turn around.

Dear Neil: Our tree is covered with a web of some sort. The leaves do not seem to be involved – just the trunk and limbs. What is it, and do we need to be worried?

This has been quite a year for barklice (Archipsocus nomas). They form extensive webs on the trunks and branches of trees. The small insects feed on lichens on the bark, but since lichens aren’t harmful to the trees, it’s a stretch to call the barklice “beneficial.” But at least they perform the function of cleaning the trunks through their feeding.

Dear Neil: We have a severe infestation of nutsedge in our garden. The garden is about to be burned out by the heat. Can we use Image to eliminate the nutsedge now and still safely plant a garden in the spring?

Yes. Read the label carefully to be sure you get the best results. You will need to make two applications 30 days apart. Water the soil deeply after each treatment to get the herbicide down into the root zone so the nutsedge can take it up.

Dear Neil: When is the best time to dig and relocate my volunteer nandina seedlings? Should I plant them into pots?

Winter is always the best time to transplant any tree or shrub. If you’re talking about small seedlings, yes, put them in pots for a few months to get them established.

Dear Neil: What would cause these brown streaks in my St. Augustine?

This is quite unusual. I would worry about a gasoline spill, a muffler burning the grass or some other type of mechanical damage to the grass. It’s not likely to be an insect or disease with such a regular pattern, although you could certainly send a sample through the Texas Plant Clinic at Texas A&M in College Station.

Dear Neil: Why would my variegated liriope have changed to solid green? How can I get it to go back, short of replacing it entirely?

The liriope in your photo is a green form. It was probably mixed in with the variegated plants or they came up as seedlings. Green plants are much stronger growers, which is why they have overtaken your variegated plants. If you want variegation, unfortunately, you’re going to have to start over.

Dear Neil: What can I do to save my mimosa tree? I love its pink flowers, but it seems to be in great distress.

This is a serious form of decay. It could be mushroom root rot. Whatever it is, it will be difficult, if not impossible, to turn around. The life expectancy of mimosas is 15 or 20 years, and judging from the size of your tree, I’d guess you’re about there. I would advise against spending big dollars on trying to save it.

Dear Neil: Do you prefer granular or spray applications for chinch bugs in St. Augustine?

I use granules, but it’s the active ingredient that matters more than whether it’s a liquid or granule. You’re going to water the granules in anyway.

Have a question you’d like Neil to consider? Mail it to him in care of the Wise County Messenger, P.O. Box 149, Decatur, TX 76234 or email him at Neil regrets that he cannot reply to questions individually.

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