Crape Myrtle: Queen of the South

By Skip Richter, Contributing Editor

I can’t imagine a summer in Texas without the beautiful blooms of crape myrtles.

When the calendar indicates the end of spring, our outdoor thermometers indicate that it is actually summer across the South. That is when the crape myrtles take center stage and, like the divas they are, refuse to bow out despite months of the unrelenting heat that characterizes Texas summers.

Crape myrtle medium-size tree

The blooms appear in terminal clusters on current season’s growth. Individual flowers in a cluster have beautifully ruffled petals with a crepe paper-like appearance.

Some of the most amazing parts of nature’s beauty are seen up close. The blooms of crape myrtle are worth a close study. Make a point to give an individual flower a close examination this coming summer and you’ll see an intricacy you’ve likely never noticed before.

Their delicate beauty belies their toughness. Some cultivars stay in bloom for more than 100 days, a feat few of our other landscape plants can match.

Crape myrtles can be seen surviving in abandoned home sites, drought-stricken landscapes and the neglect of highway plantings. Although they are not native to our state, they remind me of the bumper sticker that says, “I wasn’t born in Texas, but I got here as fast as I could!”

Texas responded by making crape myrtle the official state shrub in 1997. The city of McKinney has embraced the crape myrtle, proclaiming itself “America’s Crape Myrtle City,” while promoting annual planting events and creating a World Collection Park that is open to visitors.

Crape myrtles arrived from Asia at Charleston, South Carolina, in the 1780s and have long been a staple of southern landscapes. The famous horticulturist Liberty Hyde Bailey said over a century ago “The crape myrtle is to the South what the lilac and snowball are to the North — an inhabitant of nearly every home yard.”

Lagerstroemia indica, a native of China, was the first crape myrtle species in this country. Since it was prone to powdery mildew susceptibility, breeding efforts were initiated to seek out resistance to this disease.

The effort got a huge boost in the 1950s with the arrival of Lagerstroemia fauriei, native to Japan. The fauriei species brought genetics that not only imparted resistance to powdery mildew but also offered large blooms, increased hardiness and beautiful, cinnamon-brown exfoliating bark.

The crape myrtle breeding program at the U. S. National Arboretum in Washington, D.C. has focused on developing new cultivars with increased cold hardiness and disease resistance.

Their releases are among the best choices for our modern landscapes. They are easy to identify as each is named after a Native American tribe. Most are crosses between L. indica and L. fauriei, but some of the most recent releases include Lagerstroemia limii parentage.

Despite their toughness and resilience, there are some keys to success with crape myrtles. Most of the problems with these plants are due to mistakes made before the plants are in the ground! Late winter is a great time to plant crape myrtles, so consider the following comments and tips before purchasing and planting some crapes in your landscape.

Improved cultivars

The first key to success is with cultivar selection. More than 120 cultivars of crape myrtles have been developed over the years, and several dozen are available in local garden centers and mail order catalogues.

Many consumers make their purchase with no more forethought than visiting a local garden center and asking for a pink, white or red crape myrtle. Choosing the appropriate cultivar for your landscape is a critical first step to success. Not all crapes are created equal. Many of the older cultivars, which are often the most available in the trade, are susceptible to disease problems and often grow too large for the place where they are planted.

The perfect size 

Start by considering the size that fits the space available in the planting site. The old practice of planting what wants to be a large plant and then spending years hacking it back just doesn’t make sense. I have never seen crape myrtle plants sold with a free saw. Purchase the right cultivar and you will never need a saw!

We now have a wide range of plant sizes.

• Dwarf weeping types sprawl under 2 feet high, acting more like a groundcover than a crape myrtle.
• Dwarf bushy types such as ‘Pocomoke,’ which grows only 2 or 3 feet high, makes them great for a flowerbed or container.
• Dwarf types in the 3–5 foot range are excellent for a small space as a backdrop in a perennial border.
• Semi-dwarfs such as ‘Tonto’ grow to only 5–10 feet and are nice specimen plants or look good behind low-growing shrubs.
• Another group of cultivars reach 10–20 feet and make excellent specimens or small trees as the focal point in a courtyard or circle drive.
• If you want a tree to shade an area, consider one of many in the 20–40 foot range. The cultivars ‘Natchez’ (30’) and ‘Fantasy’ (40’) are great choices for large landscapes, bearing white blooms and very attractive exfoliating bark. Both also have great mildew resistance.

Plant-growth form varies among the shrub-and tree-type crape myrtles. Some tend toward an upright vase shape, others have a broad spreading top, and a few grow branches that hang outward and downward in a somewhat pendulous form.

The perfect color 

Crape myrtle Dynamite

“Watermelon red” is a wonderful color, but we have many more exciting color options including many shades of red, pink, lavender, purple and white. So when we say a “pink” crape myrtle, for example, you can actually choose from half a dozen or more variations on pink!

There are many new cultivars from various breeders offering features such as the Black Diamond or Ebony series with foliage that is almost black, ‘Prairie Lace’ with pink blooms bordered in white, and some truly gorgeous reds such as ‘Dynamite,’ ‘Arapaho,’ ‘Cheyenne,’ ‘Red Rocket’ and ‘Regal Red.’

I am also impressed with the lavender-to-purple color options, including ‘Catawba,’ ‘Powhatan,’ ‘Yuma’ and ‘Zuni.’

Crapes are not just pretty in the summer. Some have great fall color, too. Shades of yellow, orange and red are available depending on the cultivar, your location and the type of fall weather we have in a given year.

Crape myrtle Fantasy bark

One of the most attractive features about crape myrtles is their smooth bark. This adds a structural feature to the landscape in summer and especially in winter, when the blooms and leaves are a distant memory.

Many of the oldest cultivars were limited to a putty-tan color. More recent releases offer some exciting cinnamon brown colors in exfoliating patches along the main trunks. ‘Natchez,’ a large white-blooming cultivar, is an example of one with especially attractive bark.

Be aware, however, that it takes a few years for the trunks to reach a size where the bark can start to exfoliate and reveal the color patterns.

To spray or not to spray

Disease resistance is a big factor. Powdery mildew can really detract from a crape’s appearance and bloom production. Cercospora leaf spot, to a lesser degree, can also be a problem in some areas of the state. We now have cultivars with disease resistance, especially to the mildew, in most size categories and colors.

A crape myrtle is a long-term investment in your landscape. It makes sense to pick one that will bloom profusely in a color you love, and not require constant spraying and an ongoing pruning battle.

To help you choose a cultivar for your landscape, check out this web page listing characteristics of selected crape myrtle cultivars, which lists options by flower color, growth habit, size, mildew resistance, fall color and bark characteristics: 

This online list and the cultivars mentioned in this article are only a portion of the many choices available. So do some online research considering mature size, bloom color, bark exfoliation color, powdery mildew resistance, cercospora leaf-spot resistance and resistance to crape myrtle aphids.

The planting site

After cultivar selection, the next most important factor is planting location.

Crapes are adapted to many types of soils but prefer a slightly acidic soil. In very high pH sites they can show some iron chlorosis. In areas with very high pH soils it helps to bring in an improved soil mix to create a bed at least as wide as the mature plant width, if possible. This will provide the root system plenty of room to establish in a more favorable environment. If drainage is poor, a raised planted area is especially important.

Crape myrtles need lots of light to bloom well. Aim for a location with eight hours of sun. As the sun exposure becomes less, so will the plant’s ability to produce blooms.

Dig a hole no deeper than the container root ball. Make it a little wider and use the soil from the hole to refill in around the plant. When the hole is halfway filled, take a hose and water it in well to settle the soil. Then finish filling the hole and make a circular berm of soil twice as wide as the plant’s root ball to use as a reservoir for good, deep soakings in the months to come.

Finish the planting process by adding a 3-inch mulch of leaves, pine needles or bark. This will deter weeds, moderate soil temperatures and decompose over time to release nutrients to the growing plant.

Caring for crape myrtles

While crapes don’t need a lot of extra fertilizing, a little boost can be helpful in the first few years to get them off to a good start.

Pull back the mulch covering and sprinkle a lawn-type fertilizer evenly throughout a circular area as wide as the branch spread of the plant in late February or early March, at a rate of one cup per inch of trunk diameter for synthetic products and two cups per inch for organic products. Work it into the surface inch or two of soil with a hoe or cultivator tool. Then replace the mulch covering and water the area well.

Fill the berm with water once or twice a week in the absence of rain during the first growing season. It would be helpful to expand the berm to twice its diameter in early summer to help wet a larger volume of soil for the expanding roots.

Once plants are established, crape myrtles are quite drought tolerant and can survive on only an occasional rescue-watering, although they will bloom best if the soil is kept moderately moist.

Disease and insects

Crape myrtle with "powdery mildew"

We’ve already discussed avoiding powdery mildew by careful cultivar selection. If you already have a crape myrtle susceptible to powdery mildew, you can manage the disease with a number of natural or low-toxicity products containing potassium bicarbonate or neem oil. There are also several synthetic options that are effective against powdery mildew on landscape plants.

Aphids are the second potential problem on crapes. They feed on the leaf sap and excrete a sticky substance known as “honeydew,” quite a pleasant name considering its origin! The honeydew falls onto the leaves and other surfaces below, promoting the growth of sooty mold, an unsightly black substance.

Aphids are often kept in control by natural enemies. Some insecticides can kill these natural enemies, and excessive nitrogen applications and certain growing conditions may result in outbreaks that nature is not quick to clean up.

Some gardeners consider these aphids to not be a concern since they attract a number of different beneficial insects and support the buildup of their number in the landscape.

It is worth noting that the aphid species that is common on crape myrtles is fairly unique to crapes and doesn’t attack our other plants, such as roses, tomatoes, etc. When possible, select a cultivar that has been shown to exhibit some degree of resistance to aphids.

Sprays containing insecticidal soap can provide a quick reduction in aphids and allow natural enemies to get the upper hand. There are also systemic products which can be applied to the soil in early spring to control aphids and also a new scale insect that has recently shown up in the Dallas/ Ft. Worth area.

However, these systemics are a secondary concern in that they may harm bees which are feeding on the nectar of treated plants.

Training and pruning

Crape myrtle pruned to perfection

Crape myrtles are probably the most “butchered” plants in the landscape. In fact, someone should start a Society for the Prevention of Cruelty to Crapes!

Commercial maintenance crews continue to perpetuate the practice of cutting the plants back to the same point each winter. The dormant season is a little less busy time for landscape companies and it is much easier to just say “cut it back to ‘head high’” than to teach more judicious pruning practices. This results in unsightly stubs, which ruin the natural shape and beauty of the plant and which also promote decay of the interior wood.

Personally I think a mature crape myrtle that has been well-trained really should hardly be pruned at all.

When young, some training is advisable to develop the desired structural form by removing crowded or rubbing branches and leaving only a select number of trunks which fork at various heights to create a natural, gracefully branching form.

After the structure has been built, pruning amounts to removing suckers as close as possible to where they attach to the trunk and perhaps some other interior shoots here and there to allow the natural beauty of the smooth trunk(s) to be seen.

Less pruning results in more, but smaller blooms. More pruning results in vigorous regrowth and fewer, but larger blooms. If you prune, rather than stubbing off a branch, cut it off back where it joins another branch to avoid a “crows foot” of resprouting and to leave the plant looking more natural.

If a branch is growing where it is not desired, the sooner you remove it the better to avoid making a larger cut that leaves the plant less attractive.

Old bloom heads and twiggy growth can also be removed in winter (if you have a lot of time on your hands) by cutting much of this growth back to “pencil size” shoots.

During the summer season, remove spent blooms to promote new growth and better repeat blooming. This is most effective on the earlier-blooming cultivars.

One additional option for crape pruning is to treat the plants like perennials, cutting them back to a few inches above the ground each winter.

This method is popular with some gardeners across the South and in northern areas where crapes can be killed back to the ground in winter. This method promotes a shrubby plant form with arching growth and large blooms.

This is similar to what many Texans do with their esperanza (Tecoma stans) or pride of Barbados (Caesalpinia pulcherrima). These plants don’t die back in their native range but are treated as perennials in areas where they freeze back in winter. If you want to try this type of pruning with your crape, choose a semi-dwarf to medium-sized cultivar and experiment as to whether or not some subsequent thinning of the regrowth at the ground line is helpful.

Few plants can match crape myrtles when it comes to four seasons of landscape beauty from gorgeous blooms in the hottest months of the year, fall leaf color and architectural structure for winter interest. Now is the time to plant so your new crapes have time to establish before the heat of summer arrives.

 Consider your many options from container plantings to towering trees to set the stage for an outdoor party next summer complete with burgers on the grill, a juicy watermelon, and some homemade ice cream!

For some inspiration visit a local arboretum or botanical garden this summer, or if you are in McKinney stop by and visit their crape myrtle trail median plantings through the city or check on the development of their World Collection Park.