It is unfortunate when adverse conditions or mistakes in growing result in harm to the beautiful crepe myrtle trees, which are cherished for their vibrant flowers and unique exfoliating bark.
These trees are largely low maintenance, but there are steps you can take to get the best out of them.
Crepe myrtle trees require a full sun planting spot with good air circulation to deter disease and pest issues. They also prefer slightly acidic, well-draining soil, and while drought-tolerant, they need deep watering for profuse blooms. Pruning should also be minimal to retain its natural shape.
Whether you’re caring for a dwarf variety or gigantic specimen tree, do all you can to help your crepe myrtle live its best life!
We’ve got the guide you need to help your tree thrive — everything from ideal soil and moisture to pruning, disease prevention, and more.
Don’t miss my comprehensive Crepe Myrtle Guide to discover the best varieties, learn key care tips, explore propagation methods, and more. It’s a must-read!
Choosing the Right Location
Crepe myrtles are fairly adaptable, but where you plant your tree really does make a difference in terms of growth, overall health, and blooming.
To get the best results from those gorgeous flowers, crepe myrtle trees need to be planted in a full-sun location to thrive. This means at least 6 hours of daily sunlight, but 8 hours is ideal.
Partial shade will soon see its blossoms reduce and start to drop off, so it’s important to take the time to track the sun exposure in your landscape to find the ideal spot.
You’ll also want to choose a spot with decent air circulation to help prevent common diseases like powdery mildew.
Soil Conditions & Drainage
Crepe myrtles are thankfully not overly picky when it comes to soil types, but the soil must drain quickly.
Sitting in soggy conditions will risk the development of root rot, so opt for chalky, sandy, or loamy soils amended with some organic matter for soil that retains the necessary amount of moisture.
TIP: Take care not to use overly rich soil (i.e., clay soil or soil heavy on humus or compost) as this will result in more foliage than flowers!
If pressed, crepe myrtles prefer neutral or slightly acidic soils over alkaline (a pH of 5.0–6.5 is perfect).
The majority of garden soil in Northern America is slightly acidic, but you can perform a soil pH test to be certain.
Watering & Moisture Management
Crepe myrtles are keen drinkers, but it’s important to strike the right watering balance during different stages and weather conditions.
Mulching is also a key aspect of its moisture management for added protection, especially during winter.
Once established, your crepe myrtle will become quite tolerant to drought, but during their first few growing seasons, thorough weekly watering is necessary.
Continue to water weekly whenever the soil no longer feels moist, and take care not to wet the foliage to prevent disease.
The Importance of Mulch
Mulching around the root zone can be highly beneficial, especially for young trees.
It provides added moisture in winter or summer droughts, cuts down on weeds, both cools and insulates the roots, and even helps to prevent soil erosion for trees planted on a hillside.
Add a 2-3-inch layer of mulch (composted bark or bark chips) around the base, ensuring the mulch doesn’t touch the trunk as this can risk disease development.
Watering Throughout the Seasons
In times of extreme heat, trees should be watered twice weekly. Keeping crepe myrtles well watered in hot, dry summers or times of little rainfall helps to ensure more bountiful blooms.
If you live in an area of little to no rainfall, continue watering as if your crepe myrtle was a new planting — deeply and often.
Pruning & Shaping
Only a little at a time and only when necessary are what to keep in mind for appropriate pruning.
Overpruning and ill-timed cuts can lead to unintentionally committing “crepe murder”! Let’s look at how to avoid this mishap and the real goals behind pruning.
When & How To Prune
During the growing season, spent blooms and any leggy or twiggy growth on crepe myrtle shrubs and smaller trees can be trimmed using hand pruning shears, like these, to promote a second flowering.
Trees bloom on new wood growth, so any larger-scale/structural pruning needs to be done over winter or early spring while the tree is dormant to prevent unsightly growth and reduce damage.
Branches should be pruned conservatively, working from the base up, and cuts should be made at a 45-degree angle just above the branch collar.
You want to retain the tree’s natural shaping and maintain a healthy canopy. This means getting rid of any dead, damaged, or diseased wood to improve airflow.
Keep an eye out for branches that cross or rub against each other so that every branch is growing in the appropriate direction for the tree’s habit (upright, weeping, etc.)
Pruning appropriately from the base up also exposes the beautiful exfoliating bark of crepe myrtles to extend their interest throughout winter.
Cutting back the topmost branches must be avoided at all costs as this not only ruins the tree’s natural form but also encourages suckers to sprout near the base and roots, creating an ugly sight and doubling your pruning workload!
TIP: Always use the correct pruning tools, and ensure they are sanitized before use to prevent disease. Use hand shears for twigs and pencil-diameter branches and loppers and pruning saws for branches thicker than 2 inches in diameter.
Crepe myrtles can benefit from light fertilization, but it is not always necessary for healthy growth and is no substitute for decent care and maintenance in other areas.
If you must fertilizer, pay close attention to the type and timing of the feeds.
Selecting the Right Fertilizer
Opt for a granular slow-release fertilizer with a balanced NPK ratio, such as 10-10-10 or similar, so there are equal parts nitrogen, phosphorus, and potassium. This will prevent foliage from outshining flowers and provide a gradual feed.
Alternatively, use a fertilizer designed specifically for use on crepe myrtles, like this highly recommended blend.
Timing & Frequency
Slow-release fertilizer can be applied once to young trees at the first signs of new growth in early spring.
Mature crepe myrtles may be fed lightly twice a month throughout the spring and summer growing seasons.
Be sure to water your tree thoroughly after each application to prevent fertilizer burn.
Pests & Diseases
Many varieties of crepe myrtle are bred to be highly resistant to certain issues like powdery mildew and are not troubled by many garden pests.
Still, it’s good to be aware of the complications you may run into and how best to prevent them.
Although there are not many pests to worry about with crepe myrtle, there are a few that may appear now and then.
Aphids are translucent pale-yellow to greenish insects with black spots on the abdomen and are between 1/16 and 1/8 of an inch long.
You’ll know you have an aphid problem if leaves have yellow spots and the underside is covered in a sticky honeydew-like excretion where they have been munching.
Japanese beetles are about 1/2 an inch long with copper-brown coloring and metallic green heads.
They will often attack flowers and feed heavily on foliage, creating a lacy, skeletal appearance between the leaf veins.
Treatment: Adult Japanese beetles can be handpicked or washed off with a simple soapy water spray solution.
For large infestations, an application of neem oil can be effective in reducing populations. I use this neem oil, which is approved for organic gardening, and also have good results.
Crepe myrtle bark scale is a relatively new problem for crepe myrtles and should not be taken lightly.
These scale insects are only about 2 millimeters long, are typically white or gray as adults, and are covered with a waxy coating that almost makes them look like a fungus or bacterial infection on the tree.
Heavy infestations could severely weaken the tree, making it prone to other pests and/or diseases.
Treatment: Remove and dispose of infested branches. Horticultural oils and insecticidal soaps containing bifenthrin can be used, and systemic insecticides containing either imidacloprid or dinotefuran can also be effective.
Crepe myrtles tend to be fairly healthy trees when cared for properly. However, even with the best care, you may notice the development of one or more of the following at some point in the tree’s life.
This coats flower buds and leaves in a white-grayish powder, leading to stunted flower buds and distorted growth in the affected areas.
Treatment: Prune diseased twigs and branches if the infection is limited. For severe cases, an application of a copper-based fungicide like Bonide Liquid Copper Concentrate can aid in controlling the spread.
Cercospora Leaf Spot
Cercospora leaf spot can be identified by small yellow spots (1/4 inch in diameter) on the upper leaf surface with whitish-gray spores on the underside.
Treatment: Prune back diseased foliage, and consider using chemical control for severe spread. Recommended products are those containing myclobutanil or thiophanate-methyl such as Monterey Fungi Max Concentrate.
Pest infestations and disease can be prevented in your crepe myrtle by doing the following:
- Plant resistant varieties as certain hybrids have been designed with excellent resistance/tolerance to powdery mildew and Cercospora leaf spot
- Provide good airflow and prevent overcrowding with necessary pruning of crossing/rubbing branches and spacing trees appropriately (especially if planting in privacy screen/hedgerow formations)
- Avoid planting in damp, shady locations as fungus loves the high humidity at night and cool, mild conditions during the day.
You can grow new crepe myrtles from the parent plant using cuttings, seeds, air layering, and other methods.
Before you do though, you’ll want to make sure the tree isn’t patented as you could violate patent laws if you try to replicate the tree. Patented plants normally have ‘PP’ or ‘PPAF’ on the label.
Propagating From Seed
After flowering, crepe myrtles produce small round seed pods. Once these turn a dark-brown shade, you can snip them off using a sharp pair of clippers and squeeze out the seeds into a shallow bowl.
Store the seeds in an airtight container for planting in the following spring.
Right before spring, germinate your seeds by placing them in a pot of well-watered soil out of direct sunlight but in a warm spot until you can transplant the seedlings in pots or the garden.
Propagating From Cuttings
You can take healthy branch cuttings from the parent tree between May and August. Take several cuttings at the point where the twigs/branches meet the main branch, leaving several leaves intact on each.
Cuttings can then be planted in a mix of moist potting soil and sand for good drainage where they can remain for 6-8 weeks or until roots develop.
Side grafting is another propagation method that joins an existing crepe myrtle shoot to a common rootstock to create new growth.
Using a sharp utility or grafting knife, a diagonal incision is made in the existing Crepe Myrtle stem or rootstock at an inward 45-degree angle.
A matching cut is made in a different crepe myrtle shoot/twig known as the scion, and these are bound together using grafting tape.
Air or Ground Layering
A more time-consuming method of cloning your crepe myrtle tree is via air or ground layering.
Air layering involves wounding the surface of a healthy vigorous stem during spring or early summer and packing the wound with moist sphagnum moss to encourage new growth.
Ground layering involves taking a young, flexible stem (1-2 years old), wounding it, and bending it down to the ground so it is horizontal with and touching the soil.
The stem is secured in place with ground staples with the wounded side buried in the soil, tricking the stem into developing roots and new growth above.
Can You Trim Crepe Myrtles in the Fall?
Late winter and early spring is the recommended time to prune or trim crepe myrtle trees.
Trimming the branches in fall can cause the tree to be less tolerant to the coming harsh winter temperatures and can risk prompting the tree to send out new growth that will not have time to harden before cold weather arrives.
How Long Do Crepe Myrtles Bloom?
Depending on the variety, crepe myrtle trees can have a blooming period that lasts anywhere between 90 and 120 days.
The ‘Natchez’, ‘Tuscarora’, and ‘Muskogee’ varieties are among the longest crepe myrtle bloomers, producing blossoms from spring to early fall
Many varieties of crepe myrtle have been bred to handle diseases and tolerate poor conditions, and while choosing these resistant varieties can give you a good head start, it’s no substitute for good care practices.
If you want to enjoy a healthy and long-blooming crepe myrtle tree, make sure you can provide it with a sunny spot, the right soil type, and the right watering regimen for its age and seasonal needs, and don’t forget that less is more when it comes to pruning.