Crape myrtle bark naturally peels and exfoliates as the tree matures, revealing smooth, colorful inner layers that are one of the tree’s most prized features. But if you’re seeing white crusty patches, black sticky residue, or green growths on the bark, something else is going on. The most common bark-related concern today is crape myrtle bark scale, an invasive pest that has spread rapidly across the southeastern United States. Here’s how to tell what’s normal, what’s not, and what to do about it.
Why Crape Myrtle Bark Peels
Peeling bark on a crape myrtle is completely normal and actually desirable. As the tree grows, the outer bark sheds in thin strips or patches to reveal the smooth inner bark underneath. This exfoliating habit produces the distinctive patchwork of cinnamon, gray, cream, and pink tones that make crape myrtle trunks so attractive in winter. The shedding tends to become more dramatic as the tree ages and the trunk thickens. If your tree’s bark is peeling cleanly without any white residue, black coating, or unusual growths, there’s nothing to worry about.
Identifying Crape Myrtle Bark Scale
Crape myrtle bark scale is an invasive insect that feeds on sap beneath the bark. It’s now the single biggest pest concern for crape myrtles, and the signs show up directly on the trunk and branches. The most visible clue is white, felt-like sacs clustered along the bark, particularly in branch crotches and on the trunk. These are the coverings that female scales build to protect their eggs.
A quick field test can confirm the diagnosis: crush one of the white patches with your fingernail. If it produces a pink streak, you’re looking at bark scale. That pink color comes from the eggs inside. Each female lays 100 to 300 pink eggs per sac, and under natural conditions, a single female can produce up to 320 eggs. That reproductive rate means a small infestation can explode quickly.
The other hallmark sign is black sooty mold. As the scale insects feed, they excrete a sugary liquid called honeydew that coats the bark, branches, and even the ground below the tree. Sooty mold fungi colonize this sticky residue, turning the trunk and surrounding surfaces black. In heavy infestations, the mold is thick, smelly, and hard to miss. The sooty mold itself doesn’t directly attack the tree, but it’s a reliable indicator that scale insects are present and feeding heavily.
Infested trees also produce fewer blooms. Severe infestations can host hundreds of egg sacs and over a thousand male pupae on a single plant at peak population, draining enough resources to visibly reduce flowering.
Treating Bark Scale
The most effective treatment is a soil drench applied in spring as new growth begins. The insecticide is mixed in water and poured around the base of the tree, where the roots absorb it and carry it up through the trunk. Before applying, rake mulch away from the tree’s base so the solution reaches the soil directly. The amount you need depends on the tree’s height (for shrub-form crape myrtles) or the combined diameter of all trunks (for tree-form plants).
For best results, apply the drench between late March and May to target the first generation of crawling nymphs for the year. You can also treat later in the season, any time after the tree has leafed out and before fall leaf drop begins, though earlier applications tend to work better. Apply only one soil drench per year. These systemic treatments provide control for at least a full growing season.
Before reaching for chemicals, it’s worth knowing that natural predators can make a real difference. Lady beetle larvae are effective predators of bark scale and can significantly reduce populations on their own. Some lady beetle larvae in the Hyperaspis and Cryptolaemus groups actually look similar to bark scale, so avoid crushing anything on the trunk without checking first. University of Maryland Extension reported in 2024 that many bark scale populations collapsed or dropped sharply due to natural predators alone. You can support these beneficial insects by limiting pesticide use in your yard and planting a variety of flowering plants that provide food throughout the season.
Lichens on the Bark
Green to gray-green leafy or crusty growths on crape myrtle bark are almost certainly lichens, and they’re harmless. A lichen is a composite organism made up of a fungus and an alga (or cyanobacterium) living together. Lichens don’t feed on the tree or damage it in any way. They tend to appear more heavily on trees that are declining in vigor, but that’s a correlation, not a cause. Less vigorous trees have thinner canopies, which lets more sunlight reach the bark and encourages lichen growth.
No treatment is necessary. Once you address whatever is causing the tree to lose vigor, whether that’s poor soil, drought stress, or a pest like bark scale, the lichens typically fade on their own as the canopy fills back in. Products containing potassium salts of fatty acids are labeled for lichen removal on hardened bark if the appearance bothers you, but they should never contact the foliage.
Telling These Bark Issues Apart
- Clean peeling with smooth, colorful bark underneath: Normal exfoliation. No action needed.
- White felt-like patches that produce a pink streak when crushed: Crape myrtle bark scale. Treat with a spring soil drench or encourage natural predators.
- Black, sticky coating on trunk and branches: Sooty mold from scale insect honeydew. Controlling the scale eliminates the mold over time.
- Green or gray-green leafy or crusty growths: Lichens. Harmless. Improve overall tree health and they’ll diminish.
Bark in Traditional Medicine
Crape myrtle bark has a long history of use in folk medicine across parts of Asia, where the tree originated. The bark contains a complex mix of active compounds, including tannins, triterpenes, flavonoids, and saponins. Traditional uses included using the bark as a stimulant and fever reducer. Other parts of the plant were used for blood pressure management, blood sugar control, and digestive issues. While these traditional applications are documented, the bark’s primary relevance for most readers today is ornamental, and knowing what’s growing on it matters far more than what’s inside it.