3 Causes of Crepe Myrtle Turning Black [Treatment]

Are your Crepe myrtles leaves turning black and unattractive?

This is a gardener’s nightmare. The crepe myrtles bloom only once in spring so when the leaves start turning black it’s normal to get anxious. But this problem can be prevented and cured if you work on them tactically. 

Sooty black mold, Adverse weather conditions, and Excess fertilization are the main three reasons why your crepe myrtle leaves are turning black.

No need to worry about this because this article will guide you through the easy solutions and preventions on how to treat the crepe myrtles black leaf.

So, without making any delay let’s get started-

Why Are The Crepe Myrtle Leaves Turning Black?

1. Sooty Mold on Crape Myrtle Trees

Sooty mold is a fungus that attacks the crepe myrtle trees a lot. It turns the leaves of the crepe myrtles black. This fungus is mainly brought by insects like aphids, bark scales, whiteflies, and mealybugs.

These insects excrete a sticky substance called honeydew. Honeydew is an excellent medium for the growth of sooty mold. Sooty mold coats the whole leaves of the crepe myrtle trees.

As a result, the plant cannot absorb enough sunlight and they cannot photosynthesize very well. The lack of sunlight causes the leaves to turn black.

When the attack of sooty mold is severe the stems, twigs and, even flower buds can turn black with the black mold coating.

Now the question is how do you know if the trees are infested with aphids?

Aphids and whiteflies are very tiny and hard to notice. But the honeydew will make the leaf look oily and sticky. You will also notice ants trailing over the leaves to get sugar from honeydew.

Control Measure

It’s very important to get rid of the sooty mold fungus before it starts to drop the flower buds. Treat your crepe myrtles with the best and safest fungicide (Our Pick: Bonide Copper Fungicide). Always follow the label directions written on the fungicide.

Make sure your crepe myrtles are in an airy and sunny place. If the infestation is light, prune off the infested stems. Sterilize the pruning shears before and after working in rubbing alcohol. 

You can try some home remedies that I’m adding below. These can come in very handy for the natural control of sooty mold-

#Recipe 1:- Baking Soda Spray Recipe


  • 1 tablespoon of baking soda
  • 2 tablespoons of vegetable oil
  • 1 gallon of water
  • 1 teaspoon of liquid dish soap


  • Combine everything and give a good shake
  • Spray on the infected leaves of your crepe myrtle plants.

# Recipe 2:- Epsom Salt Spray Recipe


  • 2 tablespoons of Epsom salt 
  • 1 gallon of water.


  • Mix the salt with water 
  • Use this as an instant mixture
  • Spray this solution every other week on the leaves as long as the problem continues.

Preventive Measure

The best way to prevent sooty mold is by getting rid of the aphids and other insects as soon as possible. When you notice aphids on your crepe myrtles spray water with a strong jet to wash them off. But this method isn’t always very effective.

Because aphids and whiteflies usually attack in bulk. So, you need to pick the best insecticide for your crepe myrtle that does not harm your beautiful flowers (our pick: Bonide (BND611) – Annual Tree and Shrub Insect Control)

Plant resistant varieties like Tuscarora,’ ‘Tuskegee,’‘Wichita.’ ‘Apalachee’ ‘Fantasy’ etc.

Control the insect problems naturally by applying these homemade recipes:

#Recipe:-1 Insecticidal Soap Recipe


  • 500 ml of Alcohol
  • 1 liter of water
  • 1 tablespoon of liquid dish soap


  • Combine everything and put the solution into the sprayer.
  • Spray on both sides of the crepe myrtle leaves.  

#Recipe 2:- Neem Oil Recipe


  • 5 teaspoons of neem oil 
  • 5 liters of water 


  • Mix the ingredients and spray in the crepe myrtle plants every week.
  • You can apply this solution to your plant on a regular basis to prevent these insects.

Tip:  Use a small part of the homemade solution in a small area of your crepe myrtle leaf. If the leaf burns or discolors then dilute the solution with some water. Make it a mild solution and apply it to a small leaf again. If that particular recipe doesn’t your crepe myrtle then skip the recipe and try others

2. Extreme Weather Conditions

Extreme hot weather with the sudden rise of temperature evaporates all moisture from the leaf surface. The leaf of the plant first becomes brown. But as the moisture loss continues the leaves of the crepe myrtle start to become black.

Control Measure

There isn’t much to do in this situation. During the heatwaves give some shade to your crepe myrtles. Protect them from continuous harsh sunlight during this time. Provide them with some extra moisture depending on the hotness of the weather.

Spread a few layers of organic mulch around your crepe myrtles. This will help keep the moisture.

3. Excessive Fertilization

Too much fertilizer builds up salts in the soil. It causes the leaves to turn black. An excessive amount of any nutrient harms the roots and as a result, the roots stop functioning properly. The leaf tips start getting black first. But later the whole leaves turn black.

Control Measure

Your crepe myrtles need fertilizers to produce good-quality blooms. You need to pick a good well balanced blooming fertilizer It’s best to use a slow-release shrub fertilizer before the blooming period (our pick: Nelson Plant Food Crape Myrtle & All Flowering Trees)

When you suspect an overdose of fertilizer on your crepe myrtle water them generously to leach out the nutrients. But make sure the water gets drained nicely through the soil. When the nutrient is balanced the black leaves will soon start to turn green.


In this article, I have tried to discuss the reasons for the black leaves on your crepe myrtle in-depth information. I hope this writing helped you to figure out whether it’s a sooty mold or fertilizer problem. 

Do not forget to protect your crepe myrtles from insects on a regular basis. Otherwise, this black leaf problem will keep occurring. But the good thing is this problem is easily curable.

Share this article with your friends if their crepe myrtle has the same problem. If you have any further questions drop a comment below, and I will get back to you with a response.

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