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You can get rid of crepe myrtle fungus by combining proper pruning, improving air circulation, and applying targeted fungicide treatments at the right time.
Crepe myrtle fungus is a common frustration for gardeners, but it’s not something you have to live with forever.
Whether you’re dealing with the ugly black sooty mold, powdery mildew, or leaf spot, the good news is that most crepe myrtle fungus issues are treatable with a few straightforward steps.
In this post, we’ll walk through exactly how to get rid of crepe myrtle fungus, what causes it in the first place, and how to keep it from coming back season after season.
Let’s dig in and get your tree looking healthy again.
How to Get Rid of Crepe Myrtle Fungus: The Core Method
The most reliable way to get rid of crepe myrtle fungus starts with understanding that this fungus often thrives because of conditions you can control.
Crepe myrtle fungus typically appears as a white powdery coating on leaves, black sticky spots, or brown lesions, and it loves humid, crowded, or poorly ventilated branches.
So the first step to get rid of crepe myrtle fungus is to make the environment less inviting for the spores to grow and spread.
1. Prune Aggressively to Open Up the Canopy
One of the fastest ways to get rid of crepe myrtle fungus is to prune your tree so that sunlight and wind can reach the inner branches.
Crepe myrtle fungus spores love damp, still air, which is exactly what you get when branches are tangled and dense.
Start by removing any dead, diseased, or crossing branches, and then thin out the canopy by about a third.
You want to create a vase-like shape where the center of the tree is open and airy, because that constant airflow makes it much harder for crepe myrtle fungus to establish.
Be sure to sterilize your pruning shears with rubbing alcohol between cuts, or you’ll just spread the fungus to healthy wood.
2. Remove Infected Leaves and Debris Immediately
Another critical step to get rid of crepe myrtle fungus is cleaning up every fallen leaf and any infected foliage you prune off.
The fungus can overwinter in leaf litter and dead plant material, so leaving that debris on the ground means the spores will just reinfect your tree next spring.
Rake up all fallen leaves, bag them, and throw them in the trash, not the compost pile.
If you see leaves still on the tree that are heavily coated with powdery mildew or black spots, pluck them off by hand and dispose of them the same way.
Remember, you cannot get rid of crepe myrtle fungus if you keep leaving the source of the infection right at the base of the tree.
3. Apply a Fungicide at the First Sign of Trouble
Fungicide is your most direct chemical tool to get rid of crepe myrtle fungus when cultural practices alone aren’t enough.
Look for a fungicide labeled for powdery mildew or sooty mold, and active ingredients like propiconazole, myclobutanil, or potassium bicarbonate work wonders.
Spray the entire tree, making sure to hit the undersides of leaves where spores love to hide, and reapply every 7 to 14 days according to the label.
But here’s the trick: apply the fungicide early, as soon as you see the first white spots or black residue, because once the fungus spreads heavily, it’s much harder to get rid of crepe myrtle fungus completely.
Also, don’t spray during the heat of the day or when rain is expected within 24 hours, as that will wash the treatment away.
4. Fix Your Watering Habits to Stop Spore Spread
How you water your crepe myrtle plays a huge role in whether you’ll need to get rid of crepe myrtle fungus in the first place.
Overhead watering wets the leaves and creates the perfect moist environment for fungal spores to germinate and multiply.
Instead, water at the base of the tree using a soaker hose or drip irrigation, and water in the early morning so any accidental leaf moisture dries quickly.
Keeping the foliage as dry as possible is an easy, free way to get rid of crepe myrtle fungus without even reaching for a spray bottle.
Why Crepe Myrtle Fungus Keeps Coming Back
Even after you treat the symptoms, crepe myrtle fungus often returns because you missed one of the underlying causes.
So let’s look at the most common reasons this fungus persists, because knowing why it returns is half the battle in learning how to get rid of crepe myrtle fungus for good.
1. Crape Myrtle Aphids Are the Hidden Culprit
If you see black sooty mold, you’re not dealing with the fungus directly; you’re dealing with aphid droppings.
Crape myrtle aphids suck sap from the leaves and excrete a sticky substance called honeydew, and that honeydew is exactly what the sooty mold fungus feeds on.
So to truly get rid of crepe myrtle fungus that appears black and sooty, you have to eliminate the aphids first.
You can blast them off with a strong jet of water, or apply an insecticidal soap or neem oil to the tree in late spring when aphids are most active.
Once the aphids are gone, the food source disappears, and the sooty mold will eventually flake off on its own.
2. Lack of Sunlight Weakens the Tree’s Defenses
Crepe myrtles are sun-loving trees that need at least six to eight hours of direct sunlight to stay vigorous and resistant to disease.
If your tree is tucked in a shady spot or crowded by taller trees, it gets stressed, and stressed trees are far more susceptible to crepe myrtle fungus.
You can’t move a mature tree easily, but you can trim back overhanging branches from neighboring trees to increase light exposure.
A healthier, sun-drenched tree naturally fights off fungus, so this is a long-term solution to get rid of crepe myrtle fungus permanently.
3. Over-fertilizing Creates Soft, Fungus-Friendly Growth
Loading your crepe myrtle with high-nitrogen fertilizer forces out rapid, lush new growth, and that tender new growth is like a buffet for fungal spores.
If you’ve been feeding your tree heavily and still see fungus, your fertilizer routine might be making things worse.
Switch to a low-nitrogen fertilizer or skip fertilizing altogether, and instead, focus on building healthy soil with a layer of organic mulch around the base.
This way, you get rid of crepe myrtle fungus by not inviting it in with soft, vulnerable leaves.
When to Treat Crepe Myrtle Fungus for Best Results
Timing your treatments is just as important as the method, because you can’t get rid of crepe myrtle fungus if you spray at the wrong stage of the season.
Early spring is when the fungus first appears as buds break, so that’s your first window to apply a preventive fungicide.
Mid-summer is when powdery mildew peaks, especially during humid, warm nights, so that’s when you should be most vigilant and reapply treatments.
Late fall is your cleanup window, where you rake leaves, prune infected tips, and apply a dormant oil spray to kill overwintering spores.
By following this seasonal schedule, you’ll stay ahead of the fungus instead of constantly chasing it.
So, How Do You Get Rid of Crepe Myrtle Fungus?
You get rid of crepe myrtle fungus by combining regular pruning, thorough cleanup, targeted fungicide application, and smart watering habits.
There’s no single magic spray that works overnight, but when you address the environment, the pests, and the spores together, the fungus clears up within a few weeks.
Start by opening up the canopy, removing all infected debris, and controlling aphids if you see sooty mold.
Then, apply a quality fungicide early in the season and keep the foliage dry to prevent reinfection.
With consistency and the right approach, you can absolutely get rid of crepe myrtle fungus and enjoy a clean, vibrant tree covered in those gorgeous summer blooms for years to come.