The 'dog days' of summer usually finds trees and shrubs in a holding pattern. Their spring show is over and we must wait for the autumn leaves. One exception is the lovely crepe myrtle; Lagerstromeia indica. This Asian native has become synonymous with summer all across the American South. The large panicles of crepy-textured flowers that give us its common name brighten the landscape and put on an impressive show that few other plants can match. Climate is a big factor on how a crepe myrtle looks. Here in the Upper South where it is possible for the plant to freeze to the ground in harsh winters, we may use it as a bushy shrub that we keep pruned. We also maintain small, multi-trunked trees that top out at about 15 to 25 feet. These are quite attractive if the lower limbs are pruned for the first 5 to 7 feet to show off the exquisite, peeling bark. The bark continues to peel as the tree grows, revealing a shiny, polished look to the branches. They also tend to 'sucker' from the roots, so clip those sprouts to maintain a tree form. Crepe myrtles are hardy in USDA Zones 6-10 and even a little further north with protection. That's because plant breeders have worked hard to give us more cold-hardy varieties. Fifteen years ago, it was rare to see any here in west Kentucky, now they are everywhere. I even have 4 in my garden. When they are in bloom, they have a lovely light fragrance and bees, butterflies and hummingbirds flock to them.
In the Lower South, it is common to see large, single-trunked trees that grow well over 40 feet tall. I saw my first ones in that size range on the campus of Auburn University in Alabama and was totally impressed. Imagine full-sized shade trees covered in large, hot pink blooms! And it isn't only hot pink. There is a full color spectrum ranging from pure white, through many shades of pink, to purple and finally to the deepest red. I even have a red and white bi-color in my garden. However, there are no oranges or yellows, except for the stamens in the centers of the blooms. There are even some cultivars with dark or reddish toned foliage. You can dead-head for a prolonged bloom season or let the attractive seed heads develop. The seeds are viable once they have dried and you can even grow your own by saving them indoors and planting them in the spring. Just remember, like Forrest Gump's box of chocolates, “you never know what you may get.” Chances are, the seedling won't favor the parent, but if that doesn't bother you, try some. I've even had volunteers pop up in my garden.
Crepe myrtles bloom on new wood, so prune to shape in late winter or very early spring, however don't commit 'crepe murder'. This term was coined to describe the practice of chopping back the plant severely so that each winter there are only a few trunks forlornly sticking out of the ground. Since crape myrtles bloom on new wood, this practice encourages new growth with heavy bloom set. Sometimes the blooms are so huge that they weigh the slender new growth branches down to the point of breaking. These trees have a pleasing, natural shape on their own and I only prune to remove rubbing branches and to keep an open and airy crown. (with one notable exception) Some gardeners comment that the drastic pruning is the only way to keep the plant small enough for its space, however there are so many different sizes and forms, why not choose one to fit the space as opposed to chopping your plant? I do have one crepe myrtle that I do battle annually. It was supposed to be a dwarf variety that wouldn't grow over 8 foot tall, but I bought it at a 'big box store' for just a few dollars. This creature wants to be 20 feet tall and works hard each year to overtop my roofline. I have to prune it hard each spring to keep it from fouling my gutters because it is too close to the house. I still try to prune so it looks natural, but every year I wish it were somewhere else. I do get many compliments on it from visitors, so apparently, it is worth the trouble. Just remember, if you need a specific size cultivar, purchase it from a reputable nursery or garden center.
Crepe myrtles aren't picky about soil and tolerate average fertility and acidity well. Since they are a summer-loving plant, heat and humidity doesn't faze them either. Plant in full sun or in an area that gets at least 6 hours of sun daily. My 'monster' gets about 8 hours on the east side of my home and it obviously thrives, but there are a few pests or problems to watch for. Aphids tend to enjoy them, and powdery mildew plagues some cultivars, however newer varieties have been bred to withstand the fungus. There is also a new problem that has surfaced since 2004: Crepe Myrtle Bark Scale. These scale insects cover the branches and leaves and they look like black mold. Moisture drips from infected trees and that is actually the poop from the scale...uggh! About the only cure for this is a systemic insecticide, but luckily this scale has only surfaced in a few places in the far south.
Crepe myrtles are long-lived. There are even some at George Washington's estate on Mt. Vernon over 100 years old, so plan on having them around for a very long time.