GARDENER'S MAILBAG

Crape myrtle problems merit professional help

By Neil Sperry | Published Wednesday, August 30, 2017

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Dear Neil: We have a crape myrtle that developed white spots on its bark this summer. Someone told us to spray the spots with alcohol, but that doesn’t seem to have helped. Now there are orange wasp-like insects flying around it. Do you have any idea what is going on?

The white spots on the bark might be crape myrtle scale, a relatively new insect first observed in Richardson in 2004. It has since spread to other parts of the state. They look like large mealy bugs, and it’s possible to have many of them on a plant. They exude sticky honeydew which might be attracting other insects, but the scales don’t do a lot of permanent damage. Sooty mold (black) may grow in the honeydew. If it is the scale, the remedy is to apply a systemic insecticide in mid-May. However, I’m not completely convinced that’s what you have just from the description. Take a photo or sample to a Texas Certified Nursery Professional.

Dear Neil: We have bare spots beneath our live oaks. We put new St. Augustine sod in eight years ago and it has gradually disappeared. I understand it’s the competition from the live oaks’ roots plus the lack of sunlight. Thoughts?

Your understandings are correct, although I think the scales tilt heavily toward the side of excessive shade. St. Augustine needs at least five or six hours of complete and direct sunlight daily. With less than that it will thin and die. Not only do live oaks spread and cast very heavy shade as they grow larger, they also hold their leaves almost all year so the St. Augustine almost never gets much direct sunlight. It’s probably time to start planning a shade-tolerant groundcover such as mondograss, liriope or English ivy.

Dear Neil: We have two bearing peach trees. However, the peaches disappear literally overnight. Do squirrels do that? How can I deter them?

That wouldn’t be squirrels if the fruit are disappearing at night. It sounds a lot more like raccoons or possums. You might try a humane trap at the base of one of the trees. It won’t be easy. Both animals are very cunning.

Dear Neil: These camellia bushes were planted this spring. I have them on a timer that waters them every morning for 90 minutes with a drip irrigation soaker. I was gone for 10 days and came home to find this. Can it be saved?

The one in the center is gone. I can’t imagine it can be saved. I can’t speak to the one on the left, but it looks like it is struggling, too. Be sure the soaker hose is watering to the bottoms of the root systems. I would much rather see you watering new shrubs by hand with a water breaker or water bubbler so that you can saturate their soil balls. Then wait until they begin to dry out again (probably a couple of days) before you water again.

Dear Neil: We have a pasture with beautiful bluebonnets and other spring wildflowers. Unfortunately, it also has grassburs. Is there a product we can use to eliminate the grassburs without hurting the wildflowers?

That’s a tough question, and the timing is going to be close. Wildflowers germinate in September. You have to apply your pre-emergent weedkiller to prevent germination of the grassburs in early March with a booster shot in early June. Whether that June treatment would be dissipated by early September is the challenge. Try a small area one year to see what happens. Talk to a farm supply dealer or Extension agronomist who works with pastures.

Dear Neil: I am overrun with armadillos, skunks and now moles tearing up my yard. What insecticide can I use to get rid of whatever is attracting them?

I have used humane traps very successfully to catch armadillos. I make a wide “funnel” out of chicken wire and extending both directions out from the trap. We place it in the path where we know the armadillos head toward their tunnel. We’ve captured more than 70 over the years. Moles are attracted to earthworms as well as insects, and I’d prefer not to go on record as recommending controls for earthworms (they’re beneficial). Use the traps for the moles. A hardware store or farm supply store can demonstrate how to install them. As for the skunks, I’m going to leave that up to you working with an exterminator or wildlife management specialist. Skunks are efficient carriers of rabies, plus they have one other bad habit. But I don’t think applying insecticide to your entire landscape is going to offer much long-term help.

Dear Neil: I have two goji berry plants. Sometimes they look good, and sometimes they look bad. They do not bear fruit. What information can you provide me?

I won’t try to bluff you. I have never grown goji berry plants, nor have I known anyone who has. I find extremely limited information on them online, and it all seems to apply to northern U.S. and Canadian regions. I would categorize them as extremely speculative. Here is a link from Penn State, one of America’s most respected agricultural schools: extension.psu.edu/plants/tree-fruit/news/2014/goji-berry-culture.

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 mailbag@sperrygardens.com. Neil regrets that he cannot reply to questions individually.

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