Why is my crepe myrtle's bark turning black?

Crepe myrtles are everywhere in Collin County, and every summer we get calls about bark turning black or leaves getting a white, dusty coating. Both are common and both are usually fixable.

The white dust: powdery mildew

Powdery mildew shows up as a white or grey film on new leaves and flower buds, especially in humid weeks and on trees planted in tight, shady spots with poor airflow. It rarely kills a mature tree but it stunts growth, curls leaves and ruins the bloom. Treatment is a fungicide applied to the canopy, plus thinning the interior so air can move through.

The black bark: sooty mould from scale or aphids

If the trunk and branches look like they have been dusted with soot, the usual culprit is crepe myrtle bark scale or aphids. Both excrete a sticky honeydew, and sooty mould grows on that. Look for small white or grey felt-like bumps on the bark — that is the scale. Treatment is timing-dependent: a soil-applied systemic in spring, or a dormant-season application, plus washing the trunk. We can identify which one you have from a photo.

What not to do: topping

Cutting a crepe myrtle back to stubs every winter ("crepe murder") creates dense clusters of weak shoots that hold moisture, block airflow and invite exactly these problems. Proper pruning removes crossing branches, suckers and interior clutter and keeps the natural vase shape.

What we do

Our crepe myrtle treatment visit covers a canopy fungicide, scale treatment where needed, and corrective pruning. If a tree is too far gone we will say so and talk about replacements that suit the spot.