Introduction

The Crepe Myrtle is a fast-growing, small to medium-sized deciduous tree that produces large, colorful flowers over a long period from midsummer to fall. The foliage is attractive in fall and the textured bark provides winter interest. Another common name is southern lilac. It is typically cultivated as a multi-trunked flowering tree grown throughout the warmer climates of the world.

It is native to the Indian subcontinent, southeast Asia, northern Australia and parts of Oceania. Its genus was named after the Swedish merchant Magnus von Lagerström, who supplied Carolus Linnaeus with plants he collected.

The Crepe Myrtle may be the most widely grown ornamental shrub in the southern United States. In the summertime, the showy blooms last for several months, withstanding high temperatures, punishing heat, and powerful sunlight.

Flower colors include pink, red, purple, and white, depending on the variety. Most grow 15 to 25 feet tall and wide, with some shorter varieties growing only 2 to 5 feet tall. Dwarf varieties can be grown in containers.

Recommended Varieties

Several award-winning selections from the U.S. Arboretum offer excellent disease resistance and cold tolerance. 'Sioux' grows 13 to 20 feet tall with white to gray textured bark and a flowering period from July until frost. 'Yuma' is a dwarf form, reaching only 4 to 11 feet tall, with red flowers, tan bark, and maroon fall foliage. Both feature powdery mildew resistance and are widely available.

For containers and small spaces, consider dwarf "mini" varieties that grow less than 2 feet tall. 'Pocomoke' produces rose-red flowers and reaches only 8 inches tall. 'Chickasaw' offers fuchsia pink blooms at the same compact size. These varieties flower as prolifically as full-sized crepe myrtles and can be grown in containers or hanging baskets.

For colder climates, many new cold-hardy varieties are now commercially available, extending crepe myrtle cultivation beyond traditional southern regions.

Ongoing Care

Apply a layer of compost under the tree each spring, spreading it out to the dripline (the area under the outermost branches). Add a 2-inch layer of mulch to retain moisture and control weeds, keeping mulch a few inches away from the tree trunk. Water plants during the summer if rainfall is less than 1 inch per week. Flowers are produced on new wood, so prune back weak, spindly growth in spring to encourage better flowering. Prune off dead, diseased, and broken branches anytime.

Propagation Methods

Crepe myrtles can be propagated using pretty much every method out there. Cuttings, divisions, seeds, and layering all produce good results.

For seed starting, stratify seeds for 60 days. Best results can be had using the paper towel method. Sow seeds into a paper towel inside a plastic zip-top bag, moisten and place in the fridge for 2 months, then place the bag under growlights. As soon as the seeds sprout pot them up into 4" pots. Transplant into the ground once nighttime temperatures stay above 50 degrees. Seedlings started in the spring will often bloom during their first year.

Crepe myrtles have a habit of suckering - putting up new shoots out of the ground. With most varieties, you can carefully dig out these suckers along with some roots and have a new plant.

Softwood and hardwood cuttings both work fine. Rooting hormone and frequent misting dramatically improves cutting success.

Frequently Asked Questions about Crepe Myrtles

Can I plant a crepe myrtle where a tree died of verticillium wilt?

Yes. Verticillium is a soil borne fungus that persists for years after it kills a susceptible tree, and it is a genuine reason to be careful about replanting a maple, a smoke tree or a redbud on the same spot. Crepe myrtle is not on the susceptible list, so a site that lost a Japanese maple to wilt is a reasonable place to put one. The soil does not need replacing.

What problems should I expect instead?

Crepe myrtle trouble is nearly all foliar rather than root related. Powdery mildew is the main one, appearing as a white bloom on new growth and flower buds in humid weather, and it is worth avoiding by choice of plant, since the resistant selections listed above were bred for exactly this. Leaf spot and tip blight turn up in wet seasons and are usually cosmetic on an established tree. In the warm, wet lower south a root rot can affect crepe myrtles, though it is far less common than the leaf diseases.

Site and care prevent most of it. Full sun dries the foliage early in the day and is the single best defense against mildew, soil that drains freely protects the roots, and enough water through summer keeps the tree growing steadily rather than stressed. Space plants so air moves between them, and clear fallen leaves at the end of the season where leaf spot has been a problem. Given those conditions, a crepe myrtle is generally a trouble free tree.

What fertilizer should I use, and is a high phosphorus feed better for bloom?

A complete, balanced general fertilizer is what these plants want. Ratios such as 8-8-8, 10-10-10 or even 20-20-20 all fit, and any of them works applied at the rate on the label. There is no need for a specialty product, and brand matters far less than timing and quantity.

Apply once in early spring as growth begins, since crepe myrtle flowers on wood it grows the same season and an early feeding supports the shoots that will carry the flowers. Stop after early summer. Feeding late in the season pushes soft growth that has no time to harden before frost, which is exactly the tissue that dies back in winter, and that matters a great deal near the northern edge of its range. A newly planted crepe myrtle needs no feeding at all; wait until it is growing in spring.

On the high phosphorus question, which comes up constantly: it is not the answer. The idea that a high middle number forces bloom is persistent folklore, and on a shrub that flowers freely on new growth it explains nothing. Phosphorus does not move much in soil, most established garden soils already hold plenty, and repeated applications simply build a surplus that washes into waterways. If some of your plants perform and others do not, the difference is far more likely to be sun, water, drainage or root establishment than the ratio in the bag.

What is worth doing instead is a soil test, which your county extension office can run and interpret. And go easy overall: excess nitrogen buys leafy growth at the expense of flowers, and over-fertilizing browns leaf tips in the same way overwatering does.

Why is my crepe myrtle growing so slowly?

Take these in order.

Sun. These perform best in full sun all day. Anything less slows growth and thins bloom, and a plant that was in the open when you planted it may be shaded now by something that has grown since.

Water, which is usually the real limit. Crepe myrtle tolerates drought, but tolerating and thriving are different things. It responds strongly to steady moisture through the growing season, and deep soakings during dry spells do more for growth than anything else on this list.

Roots that never left the root ball. A plant that fails to push roots out into the surrounding soil stays stunted for years, and it is the usual explanation for a shrub that sits and sulks. Poor planting, a pot bound root system that was never teased apart, or buried rubble and rock under the hole all produce it.

Soil fertility. Average or better is what you want, and a soil test settles it.

The label on the plant. Mature sizes vary with climate and conditions, and some selections are simply slower and smaller than the species. There is also a real chance of a mismarked plant, especially where a second trade name is attached that no reference recognizes. Comparing your flowers against a known plant of the same variety is the practical way to check.

Four plants set out together that reach only four to five feet in three years are behind, but nothing on that list is hard to fix, and your extension office can help you work through the cultural causes locally.

The leaf tips are brown and the plant will not bloom

Watering twice a week is often too much. Heavy, frequent watering stunts growth, delays flowering and browns leaf tips just as reliably as drought does, and over-fertilizing produces the same brown tips. Cut back to one deep soaking a week through the hottest part of the year and stop feeding.

To water correctly, ignore the surface and dig. Push a finger several inches down and aim for soil with the dampness of a wrung out sponge, neither soggy nor dust dry. On a recently planted shrub, check the original root ball and the surrounding soil separately, because they dry at different rates and the root ball is the one that matters first. Then check your own work: water, wait a few hours, and dig down to see how far it actually went. Most people are surprised. Several inches of organic mulch over the root area, kept off the stems, evens out the moisture and suppresses weeds.

On bloom specifically, a newly planted crepe myrtle often takes a season to settle in and may flower late or not at all in its first summer.

My crepe myrtle looks healthy but did not bloom this year

A tree with excellent foliage and no flowers usually points to one of four things.

Too much shade is the first to rule out, since crepe myrtles need full sun to flower well.

Weather, if the tree bloomed well last year and was not topped hard. Late frosts nip opening flowers, and unseasonable cold or heat suppresses flowering across a whole region. Those trees recover and bloom normally the next season.

Excess fertilizer, which is a common cause on a young tree that has never flowered reliably. Heavy feeding produces leafy growth at the expense of flowers, so scale back.

Pruning at the wrong time. Crepe myrtles set their flower buds on shoots that grow during the current season, not on the previous year's branches, so late spring and summer pruning removes the very branches that would have flowered. Prune in late winter or early spring before growth starts, and the tree fills in and flowers normally on the new shoots.

A vigorous, healthy-looking tree is close to answering the question on its own: give it full sun and consistent water through the growing season, resist the urge to feed it, and give it time.

How should I prune a crepe myrtle?

Thin and shape in late winter. Because the plant flowers on the current season's growth, that late winter pruning is what generates the flowering shoots, and light shaping is all a mature plant needs.

Do not top it. Cutting every stem back to the same knuckle each year is the commonest crepe myrtle mistake in landscapes: it produces a mass of weak, whippy shoots that flop under the weight of the flowers, and it spoils the smooth trunk that is the best thing about the plant. Remove crossing branches, thin the crowded interior, take off spent seed heads if you want them gone, and leave the framework alone. Dead, diseased and broken branches can come off at any time.

My newly planted crepe myrtle is dropping its leaves

That is usually transplant shock, particularly in hot dry weather or where the plant rode home exposed to the wind in an open truck. Leaves coloring, drying and dropping is how the plant sheds demand its damaged root system cannot meet. A plant set out in fall may show nothing encouraging until new growth appears in spring, so patience is most of the treatment.

Two things determine whether it recovers.

Planting depth. The plant must sit at the level it grew in the container, with the root flare at or slightly above the surrounding grade. Planting too deep is the commonest killer, and a plant set deep declines slowly no matter what else you do. In heavy clay or over rock, plant slightly high rather than slightly low. Backfill with the soil that came out of the hole, since a rich pocket of amended soil in clay holds water and discourages roots from leaving it.

Watering, done deliberately. Build a low ring of soil around the plant to make a basin over the root ball. Fill it, let it drain completely, then fill it a second time, once a week. That puts water directly over the root mass and lets it soak through the whole depth of it, which a hose left running for a minute never does.

Where the plant came from a nursery days ago, the nursery is worth a call as well, both for their read on the plant and because many stand behind what they sell.

How do I plant a crepe myrtle in heavy clay?

Site it before you dig. Full sun and drainage are the two requirements, and drainage is the one clay gardens fail. A slight slope is ideal. Avoid any low spot where water collects and the place where a downspout or gutter empties, which in clay is the difference between a plant that thrives and one that sits in a bathtub. Keep it out of the path of strong winter wind, and leave room for the mature size of your particular cultivar rather than the size of the plant in the pot.

Then dig it wide and shallow:

  • Loosen a wide area, two or three feet out in every direction, going only as deep as the container is tall. A deep hole in clay lets the plant settle and sit low.
  • Rough up the walls of the hole. A spade slicing wet clay leaves a smooth polished face that roots do not readily cross, so scuff it with a fork before the plant goes in.
  • Deal with circling roots. If the root ball is wound around the inside of the pot, tease those roots loose or cut them and aim them outward. Roots left in a circle stay in a circle.
  • Set it at the depth it grew in the container, or half an inch higher, never deeper, then water thoroughly to settle the soil and close air pockets.
  • Mulch several inches deep over the whole disturbed area, kept off the trunk, since mulch piled against bark holds moisture where it causes rot.

Then watch the water, which is the single most important thing you will do. Aim for soil about as damp as a wrung out sponge, checking with a finger rather than a calendar, and apply water slowly and generously so it reaches well down and the roots follow it there. Clay has one trap in particular: it holds moisture for a long time, so it is easy to overwater, but once it dries out it becomes genuinely hard to re-wet and water runs off the surface instead of soaking in. That combination means checking often rather than settling into a fixed routine.

Through the first year, add a deeper layer of mulch over the root zone once freezing weather arrives. Then be patient in spring, because crepe myrtles leaf out very late, later than almost anything else in the garden, and every year people give up on plants that were merely dormant. Wait well past the point where the rest of the garden has broken bud. If the top has died back, cut it to live wood or to the ground and watch for new shoots from the base.

Is early winter too late to plant one?

In the warmer zones, no. In piedmont North Carolina and similar climates, late fall and early winter are the right time to plant woody plants: the soil stays warm well after the air has cooled, roots keep growing at temperatures far below what the top of the plant needs, and a container-grown plant that goes in then spends the whole winter making roots and meets next summer's heat already established. Dormancy is the right time to move a woody plant, not the wrong one. The only hard limit is genuinely frozen or waterlogged ground.

Plant as described above, water the whole thing in thoroughly, and then keep watering through winter dry spells whenever the ground is not frozen. Winter drought is a real cause of loss in new plantings, because it is easy to assume a dormant plant needs no water. Mulch two to three inches deep in a wide ring pulled back from the trunk, do not fertilize at planting, and do not prune beyond broken wood until late winter.

Will two crepe myrtles planted months apart ever match?

Not by being planted at the same time or the same size, because size at purchase is the least important variable. What determines whether they look like a pair is the cultivar. Crepe myrtle cultivars run from three foot dwarfs to thirty foot trees with completely different habits, bark and flower colors, and 'Natchez' planted next to a dwarf will never be a pair no matter how either is pruned or how long you wait.

Find the cultivar name on the first plant's tag or ask the nursery where you bought it, then buy the same cultivar rather than the same height. If the name is genuinely lost, matching flower color and mature height on the new tag is the next best thing, and when in doubt, buying two new plants is more reliable than guessing.

Bare branches and a thin canopy in spring

Through much of the middle of the country, crepe myrtle is grown right at the cold limit of what it can take, and a bad winter shows up exactly this way. A winter that is cold, dry and windy dehydrates the wood, and a dry fall ahead of ground that freezes hard leaves it far more vulnerable. A very wet winter causes damage from the other direction, at the roots.

The pattern tells you what happened. Winter injury and drought injury both kill from the branch tips downward, so you see dead twigs at the ends with buds breaking from older wood further back and often new shoots from the base. If the tips are alive and the bare part is the interior, something different is going on: a maturing plant naturally sheds its lower and inner growth and takes on a tree form, heading toward a clean trunk with the canopy up top.

Which of those you have determines what to do. To encourage the tree form, rub or cut off the shoots coming from the roots and keep the trunk or trunks clean. To bring it back as a full shrub, cut the oldest stems right off at ground level in late winter, which forces vigorous new growth from the base. Either way you get flowers that summer, since the blooms come on the season's new growth.

If the whole plant is stunted rather than winter damaged, look underground again for a rooting problem, and ask locally, since your extension office and a good nursery will know whether crepe myrtles across your area came through the winter badly.

How far north will crepe myrtles grow?

Farther than people expect, with a change in expectations. In zone 6, and in transition areas near a coast that run to zone 7, crepe myrtle survives but is often killed to the ground in a hard winter. The roots are the hardy part, so it comes back from the base and, because it flowers on new wood, still blooms well in late summer. It simply behaves as a large perennial or a shrub rather than reaching the tree size it makes in the South.

In zone 5 the picture is tighter still, and there is no true mini or dwarf that is reliably hardy there. The plants with a real chance came out of the National Arboretum's breeding program, which set out specifically to improve cold hardiness: 'Zuni', bright purple with a pink cast, has the longest track record of coming back year after year in a Chicago garden, 'Pecos' is a deep, almost neon rose pink, and 'Acoma' is white flowered and also among the more cold hardy selections. None of them is a mini dwarf, so the honest answer is that the size you may want and the hardiness you need do not come in the same plant.

At that latitude they are grown as small shrubs, or even as a large scale ground cover, rather than as trees. Cut the plant back early each spring to within about 4 inches of the ground and it resprouts from the base, often reaching around 18 inches by midsummer and flowering heavily later in the season. What you give up is the bark, the smooth mottled cinnamon and gray that is arguably the plant's best feature, since that only develops on wood that survives several winters. A plant that dies back is not a plant that failed; it is how these are grown at the cold edge of their range, and they still flower.

Altitude by itself is not the barrier people assume. The real limits are winter low temperature and, just as important, the lack of summer heat, because crepe myrtle needs a long hot summer to grow well, ripen its wood and flower reliably. A high mountain site with cool nights and a short season will support a plant that survives marginally and blooms poorly, even where it is nominally hardy enough for the zone. In that situation a flowering shrub bred for cold climates gives a better result.

To improve the odds anywhere near the edge: site it in the warmest, most sheltered spot you have, out of the wind; insist on well drained soil, since winter wet at the roots kills as surely as cold; give it extra protection for the first year or two with a deep mulch over the root zone applied after the ground cools; choose selections known to be hardy in your area and buy from a local grower who knows which ones survive; and do not feed after early summer, so growth is fully hardened before the cold arrives. Zone boundaries run in patches rather than lines, and a suburban yard holds several microclimates, so a plant against a warm south facing wall may thrive where the same plant in an open lawn nearby does not.

Will crepe myrtle roots damage a pool liner or lift paving?

Almost certainly not. Crepe myrtle roots are shallow and fibrous rather than thick and questing, and the species is not on anyone's list of invasive rooted trees. Planted five feet from a vinyl lined pool with four feet of concrete deck in between, a crepe myrtle is a reasonable choice. No tree carries a guarantee, but this is among the safer things you can put near hardscape. A workable spacing rule is to plant at a distance roughly equal to half the mature height of your cultivar, or about a third of it in a tight space.

The real problem with that spot is the canopy rather than the roots. Crepe myrtles get wide, and a mature one leaning over a pool drops spent flowers all through the bloom season and then leaves in fall, week after week, into the water and the skimmer. Before planting, look up the mature spread of the specific cultivar and place the trunk so the grown canopy edge stays clear of the water, or accept that you have signed up for extra skimming. Two related points: match the cultivar to the space, because these range from knee high shrubs to trees over 25 feet and the word dwarf on a label covers a wide span; and prevailing wind matters more than compass direction where litter is concerned, since a tree upwind of the pool delivers far more into the water than the same tree downwind.

What can I plant under a large crepe myrtle? Roses have failed there for years.

Roses were always going to struggle there, and the same conditions will meet whatever goes in next. A mature crepe myrtle presents an underplanting with two problems at once: a dense mat of shallow feeding roots that takes the water and nutrients first, and a canopy that has been getting larger every year. Roses want six or more hours of direct sun and their own root run, and under a 15 foot canopy they have neither. No amount of feeding or spraying fixes a light and competition problem.

What does work, all of it tolerant of part shade and dry root competition once established: daylilies, the toughest option and the one most likely to succeed on the driest side; salvias, long flowering and happy in the lean dryish soil the tree's roots create; Nepeta 'Walker's Low', which makes a soft gray green mound, blooms for months and is one of the best plants there is for competing with tree roots; amsonia, the blue star, slow to settle but permanent once there, with blue spring flowers and clear yellow fall color; columbine for the shadier side, self sowing gently to fill in; chrysanthemums for color at exactly the point when the crepe myrtle is finishing; lantana where it is hardy, or as an annual where it is not, for heat and drought tolerance; and dahlias for the outer edge of the bed where more light reaches.

Planting technique matters as much as plant choice. Do not till or dig the whole bed, which shreds the tree's feeding roots and stresses it without giving you loose soil for long. Work between the roots instead: find the gaps, dig individual holes, and cut nothing thicker than a finger. Mulch the bed a few inches deep, kept off the trunk, and water the new plants separately and deeply for their first year, because they are competing for every drop with an established tree that will win. Space them for the light you actually have, with sun lovers around the outside of the canopy and shade tolerant plants close to the trunk, and on a large area plant in drifts of one thing rather than singles of many.

One tree has burned leaf edges while an identical tree nearby is fine

Crispy leaf margins usually mean the tree is under one of several stresses, and the difference between two neighboring plants is the clue.

Investigate drainage first, since uneven settlement or a layer of dense soil can leave one tree in wetter ground than the other. Check sun and wind exposure, because one may have landed in a more sheltered or shaded spot. Check your sprinkler coverage. And consider that one tree may simply have needed extra time to settle after planting while the other adjusted immediately.

If both are in lawn, look hard at what has been applied to the grass. Excessive nitrogen from lawn fertilizer triggers leaf burn, and so does drift from a broadleaf lawn weedkiller applied nearby on a breezy day.

The leaves have perfect round holes cut from the edges

Perfect, neat holes cut from the leaf margins are the signature of leafcutter bees, solitary native pollinators that cut leaf discs to line the cells where they lay their eggs. They work in daylight, the plant is not harmed, and there is nothing to treat. These are pollinators worth keeping around.

Distinguish this from a fungal leaf spot by where the damage sits: leafcutter holes are cut cleanly from the leaf margin and have no discolored rim, while a fungal spot has a dark or diseased-looking rim and sits within the leaf rather than at the edge. If you do see fungal spots, the tree tolerates them well and usually needs no treatment.

Why are branches curling inward in a twisted fashion?

Curling and twisting on a recently planted crepe myrtle can mean three different things, and telling them apart matters.

If the affected stems are flattened, wide and ribbon-like as well as curled, that is fasciation, a genetic mutation that is harmless and can simply be pruned out. If the stems are round and merely whippy and arching inward, that is ordinary vigorous growth on a young tree, which stiffens and straightens as the branches thicken.

But if you see widespread twisting and cupping of new growth across the whole plant rather than in isolated branches, that is the signature of herbicide drift, particularly from lawn weedkillers. Check whether a weed-and-feed product or a broadleaf herbicide was used on nearby lawn. Do not assume a single cause until you can rule out the others.

Anything to keep in mind about products and heavy pruning?

Apply fertilizers and any pesticide only according to their current label, at the labeled rate, with the protective equipment the label calls for. Sweep granules off pavement rather than hosing them, since anything that reaches a storm drain reaches a waterway, and store products closed and out of the reach of children and pets. Pruning that needs a ladder or a chainsaw, or that involves a large limb over a structure, belongs to a certified arborist rather than to you on a stepladder.