Dear Neil: What kind of spray should I use on my fruit trees during the dormant season, and what should I use after they bud?
A: Apply a dormant (“horticultural”) oil spray to them before their buds start to swell. It will eliminate many of the over-wintering insects as well as reducing populations of scale insects. As for spring spraying, it will vary with the crops. Texas A&M has good spray guidelines crop by crop online. Peaches and plums are the ones people ask about most frequently. Apply a labeled fruit insecticide such as Malathion when the flower buds are just showing color but before they start to open. That’s called the “pink bud stage.” The next spray would come when 75% of the petals have fallen, and that spray should be made in the evening after bee activity has stopped. Repeat the sprays on 10-day intervals until harvest. That should help prevent entry of plum curculios and other insects.
Dear Neil: I have a crape myrtle with black residue on its trunk and limbs. It has gotten progressively worse this winter. Do you think the tree will survive?
A: Absolutely! That’s sooty mold, a fungus that gets started in the sticky honeydew residue left behind by aphids and scale insects. While unsightly, it’s not harmful at all. You can use a bucket of soapy water and a soft sponge or rag to wash the trunks to eliminate it, or the sloughing bark will take much of it with it as the plant grows this year. Watch for the insects and their sticky sap coatings, and treat immediately so you won’t have more of the sooty mold. Better yet, apply Imidacloprid systemic insecticide in mid-May as a soil drench to prevent the insects ever from getting a start.
Dear Neil: We bought a home where there are yuccas. Several grow along the ground but then end up with vertical growth. Why would this be happening? I do not know how they were cared for, including trimming. They are in partial sun. What should I do for them? Do they need to be pruned?
A: Yuccas need full sunlight to grow properly. The fact that these had shade probably led to their poor growing habits. Pruning might help, but you may also want to transplant them to a spot with full sunlight. Don’t feel responsible to retain all of the prior homeowner’s plants, just as you wouldn’t feel responsible to retain old carpet or countertops indoors.
Dear Neil: Our bermuda lawn is dormant right now. It seems very thick. Should we use a lawn thatcher to thin it out, and how high should we mow the grass? Also, why do we have so many mushrooms?
A: Let’s define a couple of terms. “Dethatching” refers to flailing the grass to pull a layer of un-decomposed organic matter up from beneath the runners. That forms an impenetrable layer that keeps water and nutrients from reaching the soil. Aeration, by comparison, can break through thatch and compacted soil to allow air and moisture to reach the turf’s roots. I do not recommend dethatching since it tears up the lawn so badly. However, you can use a core aerator (pulls plugs out of the ground) if you have compacted soil from pedestrian traffic or if you do have actual thatch. That’s a task for April or May, but again, I recommend it only in very specific situations. It’s generally much more useful to scalp the grass by dropping your mower blade down to 1-1/4 inch. Remove the clippings and use them in the compost or (in moderation) in bed preparation.
Dear Neil: Is it possible to divide a century plant? I have one that has several small ones coming up around it.
A: Yes. For lack of a better term, we’ll just call those its “pups.” That’s the word used to describe similar sprouts coming up around a mature bromeliad plant. Agaves (century plants) send them up around the time that the plant is getting ready to bloom (or shortly after it has flowered). That’s because the mother plant dies soon after it blooms. The pups can be dug and separated, then replanted into new locations where they will grow larger and larger over a period of 10 to 15 years before they, too, will send up their magnificent bloom stalks. Just give the new plants ample room to grow — probably 7 or 8 feet between plants.
Dear Neil: Our old cedar shrubs were attacked pretty badly last summer by bagworms. There are still a good many hanging on the branches. Is it worth our while to pull them off?
A: It won’t be a pleasant task, but it probably would be. This year’s crop of adult moths will emerge out of those bags this spring. The more you can remove, the fewer moths you’ll have and the fewer bagworms your plants will encounter. Hopefully they’ll come off and bring the threads that hold them to the twigs with them. Left in place, they will girdle those twigs. That results in the loss of the ends of the small branches over the next year or two as they try to grow larger. By the way, have some hand lotion handy. Pulling these things off is an unpleasant job. Use an insecticide this year to eliminate them as they start feeding. They’re easily controlled.
If you’d like Neil Sperry’s help with a plant question, drop him a note in care of The Eagle, P.O. Box 3000, Bryan, Texas 77805. Or email him at email@example.com.