Beginner's Guide to Crepe Myrtle Care
The South's love affair with crepe myrtles is undeniable. In some areas, you see them on practically every street—and for good reason. Few plants can match their combination of spectacular summer flowers, colorful autumn foliage, and handsome sculptural trunks. If you're thinking of adding one or more crepe myrtles to your landscape this season, the following tips will help you make a good decision.
Selecting the Right Crepe Myrtle
Seeing a crepe myrtle (also called crape myrtle) in its full summer splendor sends some of us running to the garden shop to buy a plant the same color. But don't buy impulsively. Pay attention to the plant's tag. Make sure that it is not only the exact color that you want, but also the right size and look you hope to achieve.
Crepe myrtles range in size from dwarf selections that grow less than 3 feet tall to several that reach upwards of 30 feet. Knowing the mature height of a plant before you buy it and planting the proper size for the site will save you much heartache and backache in the future.
Crepe myrtles can grow in USDA hardiness zones 6-9. If you're in the Upper South, you should also look for selections that are extra cold-hardy.
The most common species is Indica crepe myrtle (Lagerstroemia Indica), which was brought to the South from China in the early 1800s, or hybrids between this species and Japanese crepe myrtle (Lagerstroemia faurei). Blooms come in pink, purple, red, and white, and some of our favorite varieties are "Catawba," "Osage," "Natchez," and "Miami."
Where to Plant Crepe Myrtles
Crepe myrtles have many landscape uses. Planted together, they make a large deciduous hedge or screen. A single tree can create a distinctive focal point, while a pair framing a front door greets visitors with a warm Southern welcome.
Be sure to choose the right size for your needs. The larger types need room to grow without encroaching on buildings, power lines, or walkways. Medium-size selections that will grow from 12 to 15 feet are perfect for a small courtyard or garden home. The dwarf selections look great in large containers, foundation plantings, and even incorporated into perennial beds. Also, remember that crepe myrtles love sun. The amount of flower production is greatly reduced in light shade, and full shade can prevent blooming altogether.
Where Not to Plant Crepe Myrtles
Crepe myrtles provide beautiful, colorful blooms starting in early summer, but by August through October, the spent flowers start to drop as do the leaves, making a mess in their wake. To minimize clean-up and let these trees do their thing, avoid planting crepe myrtles by a pool, driveway, walkway, porch, deck, and in front of a window.
How to Plant Crepe Myrtles
Late fall to early spring is the best time to plant. But a lot of folks buy and plant their crepe myrtle in summer because they select it while it is blooming. That works too, but watering well during the summer months is crucial to transitioning it into your garden. No matter when you plant, water your crepe myrtle well before putting it in the ground. This will help it take up water after planting.
To plant: Dig a hole about three times as wide as the root ball; test the potted plant in the hole to make sure it's deep enough and that the root ball is level with the surrounding ground; if it fits, remove the pot and plant the tree, filling in the hole with the excavated soil.
Mulch, 2 inches deep, to conserve moisture and keep down weeds. Apply a fertilizer such as Schultz Starter Plus Transplanting Solution or Vigoro Starter Fertilizer as recommended on the label.
How to Prune Crepe Myrtles for More Flowers
Once crepe myrtles have bloomed and shed their first flowers, they will set seed. The small round seedpods or capsules usually weigh the limbs down, making them sag. Using a sharp pair of clippers, cut off the seedpods. New shoots with buds will quickly appear, and you will get a second bloom. If the temperatures stay warm into the fall and you continue to remove spent flowers, you may get a third or fourth.
In the winter or early spring, it is a common practice to cut back trunks into stubs to maintain the tree's sculptural form. But this pruning practice, known as "crepe murder," can actually do more harm than good. "This ruins the natural form and encourages the growth of spindly, whiplike branches that are too weak to hold up the flowers," according to the Southern Living Garden Book.
Troubleshooting Common Crepe Myrtle Problems
As soon as crepe myrtle leaves unfurl, look for aphids. Their sugary excretions causes sooty mold. This covers the leaves, making them look black and unattractive; a bad infestation will eventually turn leaves yellow and may hinder blooming.
Control these pests by spraying with insecticides that target aphids (such as malathion, diazinon, or ultra-fine horticultural oil) in the summer as soon as they appear. Spray both sides of the foliage thoroughly, and be sure to get the tips of new shoots and flowerbuds. Repeat this treatment as necessary.
A white powdery fungus called powdery mildew sometimes attacks the leaves of many older selections of crepe myrtles. Although the disease may keep the trees from blooming when it becomes severe, most trees aren't permanently damaged.
You can prevent this problem by planting a mildew-resistant selection. For susceptible types, spraying the foliage at first sign of disease with Funginex, Immunox, or summer horticultural oil will keep the powdery mildew from spreading; repeat sprays are necessary.