How to Grow Crape Myrtles
Lawn and Garden, Trees & Shrubs by Julie Day
About Crape Myrtles
With literally hundreds of sizes and colors available, crape (or crepe) myrtles are a terrific, low-maintenance choice for prolific blooms during hot, humid summers. Nowadays, many varieties are hybrids that maximize the colorful blooms of the common crape myrtle (Lagerstroemia indica) and/or the distinctive bark, cold hardiness, and disease-resistance of the Japanese crape myrtle (Lagerstroemia faurei).
Crape myrtles bloom in midsummer, with colors including white, lavender, purple, pink, magenta, and red. After blooming, they develop distinctive seed heads, then the leaves tend to fall toward the end of autumn, leaving the colorful, exfoliating bark for the winter.
Exfoliating bark gives year-round beauty.
Selecting Crape Myrtles
Crape Myrtles truly come in every possible size and shape, from knee-high shrubby dwarf plants to towering tree forms, so it is possible to choose a variety that exactly fits your purpose. When choosing crape myrtles for your yard, there are several factors to consider including:
- Height
- Natural shape (shrub vs. tree)
- Flower color
- Amount of bark exfoliation
- Disease resistance
Printable list of crape myrtle varieties (PDF 61kb)
Fading blossoms enrich the color palette of this deep red variety.
Planting and Growing Crape Myrtles
Crape myrtles can be grown in USDA hardiness zones 6-10, although in zone 6 they’re likely to die back to the ground in winter. They like humidity and, once established, can tolerate quite a bit of drought. They flower best in full sun (at least six hours per day). As for soil, most any kind will do, as long as it’s well-drained. The ideal soil pH is neutral to slightly acidic.
Ideally, crape myrtles should be planted in cool weather when they’re dormant. Dig a hole twice the size of the root ball. Soil amendments are usually unnecessary unless you’re amending the entire planting bed – small pockets of high-nutrient soil can prevent the roots from branching out properly. Plant your crape myrtle at the same depth it was in the nursery pot, and backfill with loosened soil. Then water thoroughly and apply 3-5 inches of mulch.
Seed heads can be removed, or left for late-season interest.
Water newly planted crape myrtles at least once a week if dormant and in cool weather, and up to five times a week if planted during hot weather or in very sandy soil. Water new plants regularly for about two months, and water during drought for better blooms and healthier plants.
Crape myrtles benefit from annual feeding with a general-purpose or high-nitrogen fertilizer, in early spring as soon as you see leaves. If you want to fertilize twice, do the second application about two months later. Slow-release fertilizer can help prevent rapid sucker growth that is vulnerable to diseases and insects. Take advantage of the toughness of these plants – too much fertilization can actually result in excessive leaf growth and fewer blooms!
Size and Pruning Crape Myrtles
Depending on the variety, crape myrtles can have different shapes. The miniature, or dwarf, varieties are generally bred to have lots of branches, and they tend to look shrublike and shouldn’t need pruning unless they are growing unevenly. Medium and large varieties tend to develop sucker growth, or small shoots at the base of the trunk. These may be pruned off if desired, and the entire plant may be pruned according to your tastes. For varieties that bloom before mid-July, deadheading can often result in a second blooming.
Crape myrtles bloom on this year’s new growth (sometimes called “new wood”), so prune during late winter before growth starts. Fall pruning, especially in warm climates, can result in a quick growth response that prevents dormancy and makes winter freezes potentially deadly.
There are two schools of thought, and quite a bit of debate, about larger pruning jobs. Some gardeners like to lop off all stems at a uniform height each year, leaving branch stubs in the winter that flush out into a ball of growth in the spring. This is useful if you want a uniform border and height control, but it can result in bunchy growth and knobby stems that may be more susceptible to aphids and disease.
Other gardeners decry this method as “crape murder” and adopt a less aggressive approach that conforms more to the natural size and shape of the plant. Most growers and researchers agree that only light pruning is necessary for plenty of blooms, so the choice is really yours.
To achieve a graceful tree shape that shows off the lovely bark, first remove all but 3-5 strong trunks. Then remove lateral branches on the bottom half of the tree. Make “heading back” cuts on long, leggy limbs to encourage branching. Don’t overprune in the beginning – make the basic cuts and then allow the plant to grow, and continue shaping over time.
The best decision about the size of your crape myrtle is made when you buy it. Buy the right variety to fit the space! If you buy a 15′ variety and try to keep it 7′ tall, you will prune yourself silly. Instead, buy a 7′ variety, and you will find yourself with an incredibly low-maintenance plant.
Pests and Diseases for Crape Myrtles
The most common scourge of crape myrtles is powdery mildew – particularly during hot, humid days followed by cool, dewy nights. Another common problem is leaf spot (Cercospora lythracearum), which looks like dark brown spots on the leaves, which then turn yellow and fall off. Both can be controlled with a general fungicide, and some cultivars are more resistant than others. Crape myrtles can also be affected by root rot (caused by poorly-draining soil), and sooty mold (caused by the excretions of pests such as aphids).
Further Information
- Crapemyrtle Varieties, Clemson University
- Crape Myrtle Culture, University of Georgia
- Crapemyrtle Q&A, U.S. National Arboretum
- Crepe Mytle Issues, Mobile Press-Register
2 Comments on “How to Grow Crape Myrtles”
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August 16th, 2008 at 08:25
How do I stop growth of new plants from areas where the root was cut during landscaping activities? I’ve thought of using Round-Up but I’m afraid of damaging the original 21-yr old tree!
March 10th, 2009 at 10:14
Crape Myrtles are new to me. Mine have some type of problem on ’some’ of the branches. Looks a little like a gritty, bumpy, discolored growth before dieback begins, (almost how poison ivy looks on a persons skin). I am guessing it to be a disease as the only insect pests are j. beetles, ants, some spiders. I’ve search the web and found little. I would rather treat for the specific problem then a general disease control. Any ideas or good sites?