Crepe myrtles are small trees with lush green leaves that make them a favorite in gardens and landscapes throughout the Southern United States. If you ever notice yellow leaves on crepe myrtle, you’ll want to address the issue sooner rather than later.   

As highlighted by Marietta’s trusted arborist services provider, we’ll dig deeper into what causes crepe myrtle leaves to turn yellow.  

Reasons Crepe Myrtle Leaves Turn Yellow  

Crepe myrtle leaves turning yellow could represent a wide range of issues. Understanding the underlying cause can help you determine the best course of action. Common reasons crepe myrtle leaves turn yellow include the following.  

Seasonal Changes and Aging  

Like many other trees, crepe myrtle leaves can turn yellow, red, or orange during the fall. The leaves will also turn light green, then yellow or brown as they age and naturally fall from the tree. In such cases, you shouldn’t worry when the leaves turn yellow.   

Crepe myrtle leaves may also turn brown because of a fungal infection, a cold spell, or poor plant care, such as overfertilizing or underwatering.  

Improper Watering  

Overwatering, underwatering (or drought), and impurities in water can all cause the leaves of crepe myrtles to turn yellow.

Too much water will cause the roots of your crepe myrtle to rot away. Adding some mulch around the tree’s base or planting water-loving plants nearby may help to address an excess water issue.  

Regarding too little water or drought, simply watering more often, especially during the summer months, should solve the problem.  

Dealing with impurities in water may prove a bit more challenging. Start by checking your water source. For example, crepe myrtles don’t respond well to high levels of chlorine or minerals present in well water.  

Pests and Disease  

Yellow leaves on crepe myrtles could indicate a pest infestation. Various pests, from aphids and scale to mites and whiteflies, can attack crepe myrtles and cause the leaves to turn yellow. Aphids, for example, suck nutrients and transmit plant viruses using their long, tube-like mouthparts.  

Regarding disease, the most common one that affects crepe myrtles is phyllosticta leaf spot. This fungus produces small spots on the leaves that change color from yellow to brown, then green, then black.  

Another common disease that may turn crepe myrtle leaves yellow is the cercospora leaf spot. This fungus can cause significant damage to your plant. It features circular, yellow-orange spots with a dark center.  

Keep an eye out for symptoms of a pest infestation or disease, and seek professional help from a certified arborist.  

Poor Soil Health  

The leaves of crepe myrtle may also turn yellow because they lack sufficient nutrients, such as nitrogen and potassium. Solving the issue may mean simply applying the right type of fertilizer to your soil.   

However, exercise caution to avoid overfertilization, which can also cause yellowing or browning of leaves. pH levels matter too. You want balanced pH levels, as extremes make it difficult for plants to absorb nutrients.   

Adding lime or sulfur to the soil will help improve pH levels depending on a soil acidity test. Most local garden centers will have an affordable soil test kit and agents that enable you to alter the soil’s pH accordingly.  

Contact Your Local Tree Experts  

Trees need intensive care to grow healthy and thrive. Trust the certified arborists at SoutheastTree for your tree care needs. As a full-service tree company, we offer the following tree care services:  

• Tree removal  
• Tree trimming and pruning  
• Emergency tree service  
• Golf course tree maintenance  

Call us at (770) 977-8733 for more information about what causes yellow leaves on crepe myrtle or to learn what causes leaf scars on trees.