How to Grow & Care for Crepe Myrtle (Lagerstroemia indica)

The crepe myrtle (Lagerstroemia indica)is a species of small, beautiful tree native to Asia that has naturalized in the Deep South of the United States. So often used in landscaping is Lagerstroemia indica that as you travel around some areas of the country, that you will see its presence in almost every yard. Though certainly not unique, its common use is a testament to its stunning blossoms, peeling bark, and attractive fall foliage that gives the crepe myrtle unrivaled all-season interest.

Common Name	Crepe Myrtle
Botanical Name	Lagerstroemia indica
Family Name	Lythraceae
Plant Type	Deciduous tree / large shrub
Mature Size	6-25 ft. tall, 6-20 ft. wide
Sun Exposure	Full sun
Soil Type	Average, medium moisture, well-drained
Soil pH	6.0-6.5
Bloom Time	July-September
Flower Color	Red-rose
Hardiness Zones	USDA 6-9
Native Area	China, Indochina, Himalayas, Japan

Crepe Myrtle Care

This species of Lagerstroemia is generally a lower maintenance selection. Though low maintenance, there are some things you can do to help get the best blooms from your crepe myrtle and ensure that your tree thrives. As always, it all starts with planning and selecting the right location. Crepe myrtles tolerate pollution, so they can handle being closer to a street, but their smaller size does not allow the species to act as a street tree. Decide in advance if you want your plant to be a shrub or a tree in form and plan for that growth. The rest of the care is all about site conditions and some basic maintenance. Knowing where to plant your tree and how to take care of it will ensure you get the most beauty for your buck.

Tip

Crepe myrtle, though often listed as a shrub, is not really a shrub or low-growing tree. Be prepared for it to grow up to 25-30 ft. tall. Sometimes owners of crepe myrtles who want them to stay shrub-sized will cut the main central branch (i.e., top it),which permanently ruins their growth structure and can make them extremely unsightly and sickly in the long run. Topping crepe myrtles is such a common mistake it has been dubbed "crepe murder." So, if you are certain you don't want a tree and only want a shrub, it might be best to pick a different plant!

Light

To get the most prolific blooms with the best color from your tree, pay attention to the amount of sunlight. Crepe myrtle needs full sun to thrive. You should place it in a spot in your landscape that gets at least six hours of sun a day. Anything less and you will notice a big fall off on blossoms.

Soil

Crepe myrtle is not too demanding regarding soil pH, but it prefers neutral or slightly acidic soil over alkaline soil. However, it does get finicky with its soil moisture. The soil must be well-draining; a crepe myrtle cannot tolerate standing water, because it is susceptible to root rot. You will also want to avoid very rich soil since this produces more foliage than the desired flowers.

Water

Unlike most trees, the crepe myrtle needs water often, especially if the soil is not moist. To bolster those beautiful blooms, you need to water the roots deeply, particularly during dry periods. As usual, you will need to water it as it is being established, but if you live in an area that does not get a good amount of rain, it is a great idea to continue watering your crepe myrtle using the same method as you would with a newly planted tree. Water your crepe with two to three gallons of water per inch of trunk diameter. It is important to only water the roots of crepe myrtle, especially if your tree does not have enough space around it for airflow; you want to avoid watering the foliage. Wetting the foliage during watering invites powdery mildew.

Temperature and Humidity

Though the USDA zone map says 6-9, growing crepe myrtles north of zone 7 can be tricky. Roots that are well-protected underground or mulched will be hardy enough to survive colder winters, but exposed branches will not make it through winters that reach less than -5° Fahrenheit. To combat this, consider pruning all branches to the soil level. Crepe myrtles bloom on new wood, so new blooms will come out yearly as the tree emerges in the spring.

Fertilizer

You will want only to fertilize your crepe myrtle very lightly or avoid it completely. Supplemental fertilizers tend to increase foliage growth which in turn inhibits bloom production. If you need to use a fertilizer, choose a slow-release fertilizer with high nitrogen content. The content can be found by reading the NPK formulation. Before fertilizing, the best thing to do is to run a simple soil test to see if your soil is really deficient or if there is another issue.

Types of Lagerstroemia Indica

Lagerstroemia indica is just one plant of a genus containing 50 or so species. Straight species of L. indica are not sold in the nursery trade so you will always be buying a cultivar or hybrid, but unfortunately, they are not often marked well and the tag will just say "Crepe Myrtle, Lagerstroemia indica."If you purchase from a reputable nursery this won't be the case and you have the chance to choose from some outstanding cultivars with amazing traits that vary from form, color, and size. Some common cultivars you may see are:

• Lagerstroemia Indica ' Enduring Summer White' – A dwarf variety with white blooms, 4-5’ tall and wide.
• Lagerstroemia Indica ''Tuskarora' - Bright watermelon pink blossoms followed by orange fall color.
• Lagerstroemia Indica 'Catawba' - Purple blooming variety, with great fall color and a rounded habit reaching 10-15' tall and wide.
• Lagerstroemia Indica 'Muskogee' – 22-25’ tall and wide, lavender-blue flowers and light gray bark.
  

Pruning

Pruning your crepe myrtle is a chore that needs to be done for a few reasons. Pruning can aid in bloom production and help beautify the plant by exposing the exfoliating bark, increasing seasonal interest, and establishing the best size and form by removing suckers and errant branches. Crepe myrtles bloom on new wood, so pruning in the winter or early spring will promote prolific blooming. If you are trying to establish your plant as a tree form, it is important to prune all but one trunk off to establish a leader. Creating a tree form, in turn, will create the chore of tidying suckers and structural pruning until a single leader is developed. A single trunk creates the stunning visual of the peeling bark that makes the Lagerstroemia indica shine even in the winter.

Common Pest and Plant Diseases

Luckily crepe myrtles don't deal with too many pest issues, but they are susceptible to powdery mildew, sooty mold, and other fungal infections. The best way to deal with these issues is, of course, prevention. To prevent these issues from arising, water the roots rather than the foliage and allow your tree to have plenty of space to air dry after rainstorms. Yearly treatment with a general fungicide can also reduce the risk of an infected plant.

From: thespruce