FLORIDA — Crape myrtles are common landscape plants. In today’s article, Gary Knox, UF/IFAS Horticulture Professor, answers common questions about this popular plant.
Q. Why is my crape myrtle’s bark peeling?
It’s normal for old bark to flake off on crape myrtles. Underneath, the new bark on many hybrids is beautiful, with colors ranging from near-white to warm beige to orange to cinnamon-brown to bright red. The colorful bark persists through winter until fading in spring, when the process starts over again.
Q. How can I get my crape myrtle to grow faster?
Crape myrtles often grow fast even without special treatment. However, regular watering and light applications of fertilizer will help crape myrtle grow faster.
Q. Why won’t my crape myrtle flower?
Crape myrtle won’t flower well in areas receiving less than six hours of direct sunlight each day. Also, when crape myrtle is planted too deep, the roots can’t get enough oxygen, stressing the plant and reducing growth and flowering.
Make sure it wasn’t planted too deep. The upper-most root should be even with ground-level or an inch or two above – never below the soil line.
Q. What’s the black stuff on the leaves of my crape myrtle?
A blackish layer on leaves is sooty mold, a harmless fungus. However, sooty mold usually indicates the presence of aphids, insects that feed on plant sap of new growth.
Aphids exude excess sap, called honeydew, onto leaves below. Sooty mold uses the sugary honeydew to grow and form a black covering on leaves.
Fortunately, aphids can be controlled by beneficial insects already in your garden. Alternatively, you can manage them by spraying horticultural soaps or oils. Once aphids are controlled, sooty mold will weather away.
Q. What’s the white stuff on the leaves of my crape myrtle?
A. Powdery mildew is a fungus that looks like a whitish powder on the tops of leaves. It occurs mostly on old varieties of crape myrtle in shady, humid locations when days are warm and nights are cool.
When severe, it may distort new growth and flower buds.
Newer hybrids are resistant to powdery mildew. A non-chemical method for reducing powdery mildew is to prune the plant to increase air movement. This helps by making conditions less suitable for this fungus.
If powdery mildew reoccurs often, you might consider fungicides. These are applied before the disease starts, when weather conditions are right for the disease, or at the first sign of disease.
Look for products labeled for powdery mildew on crape myrtle.
As with any pesticide, read and follow all label directions carefully.
Here’s a link for a publication on crape myrtle: https://edis.ifas.ufl.edu/publication/ST342