It’s shaping up to be a stellar year for North Texas crape myrtles. Many are already at prime bloom and a few have already peaked and are “making plans” for another go-round. I’m being asked many questions each day about this most popular of the Southern flower shrubs/small trees. Here are a few, along with my short-form replies.
Much of the top growth on my crape myrtles died. New shoots are growing from the ground. What happened? Should I cut the dead stems out?
That was damage done by the extremely cold weather we had briefly in January. Several varieties, including Natchez, Tuscarora, Sioux, Muskogee and Country Red were hurt or even killed back to the ground. Yes, you need to use lopping shears to remove the dead trunks carefully. Retrain the new growth back into tree form.
Why are my crape myrtles not blooming when others in my neighborhood are?
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There are several possible causes. First, some varieties bloom very early. Or you may have them growing in very poor soils and you may not be giving them enough water and nitrogen to encourage new growth. Crape myrtles bloom on new growth, hence that plant food recommendation. One of the biggest causes, however, is topping. That can delay the first round of blooms by six or eight weeks.
Why do my crape myrtle buds never open? They just sit there.
The first time I got that question, it really caused my brain to spin. I was an extension service horticulturist answering phone calls, and the caller finally got around to telling me that she’d been out of town for 10 days. That’s when I realized that her crape myrtle buds with the star-shaped patterns built into them had actually opened while she was gone, then shed and turned into plump fruit, also with star-shaped husks. She had just missed that round of blooms.
Should I prune off the seed heads once all the flowers have fallen? Does it help the plant bloom again any more quickly?
No pruning is necessary. Research from the University of Florida has shown that the plants come back into bloom just as rapidly if you find other ways to spend your summertime evenings. Plus, it’s a lot of tedious work to try to nip them all off.
Why is the bark falling off my crape myrtle?
Crape myrtles have what is called “exfoliating” bark. It peels off like a snake’s skin. In that regard, they operate just as sycamores, paper birch and several other common trees. Bark is a dead tissue, and as the crape myrtle’s trunk grows larger, the bark pops loose and peels off. That actually happens with almost all plants. It’s just not as noticeable with most of the others as it is with crape myrtles. No reason to worry. No call to action.
What is the white growth on the flower buds of my crape myrtle?
Powdery mildew. It’s the old-fashioned nemesis of crape myrtles all across the South. It impacts the new growth and first round of flower buds in May and early June, but it won’t kill the plants. You can apply a labeled fungicide, and you should also do all that you can to keep the foliage dry. Hybrid introductions of the U.S. Department of Agriculture over the past 40 years have aimed at finding mildew resistance. You will find them bearing Indian tribal names given by the renowned Don Egolf, their originator, in honor of the tribes from his native Oklahoma.
What are the white insects on the trunks of my crape myrtle?
That is crape myrtle scale, a comparative newcomer to America. It was first observed in Richardson in 2004. It has now spread to several Southern states. When you press on the insects, they will ooze red fluid. They secrete sticky honeydew residue that coats the trunks and the leaves. You won’t see these on all crape myrtles. In fact, some years you won’t see many of them at all. Predatory twice-stabbed ladybugs feed on them, and you can also apply a systemic insecticide in mid-May into early June to stop or prevent them. They are more annoying than damaging. A great deal of research is being done on eliminating them.
Why are the trunks on my crape myrtle black?
That is a fungus known as sooty mold. It uses the honeydew excreted by scales and aphids as its food source. It is ugly, but otherwise it is harmless. You can wash much of it off with soapy water. It will also fall away as the bark sloughs off the following spring.
When is the best time to plant new crape myrtles?
Crape myrtles can be planted at any time of the year, but you will want to water them by hand for their first couple of summers. Selections are best in area nurseries right now, so this might be considered to be your optimum time to buy and plant them.
I had to remove a crape myrtle that was growing too tall. Now I have sprouts coming up all over our yard. How can stop them?
They are indeed persistent. Your best bet is to use a sharpshooter spade at a 30-degree angle to slice through them. You can use a large pair of pliers to pull the severed shoots out of the ground.