Crape Myrtle Foliage Yellowing: Reasons and Solutions
In the vibrant world of gardening, one question that often arises is why crepe myrtle leaves turn yellow. Glen, a gardening expert with over 15 years of experience, shares insights into this common issue.
Crepe myrtles, known for their stunning blooms, thrive in full sun and well-draining soil with a slightly acidic to neutral pH. However, they require specific watering practices to prevent stress on the system, which can manifest as yellowing leaves.
Both overwatering and underwatering can cause yellow leaves in crepe myrtles. In established crepe myrtles, deep, infrequent watering during spring and summer encourages deeper root growth, helping to avoid underwatering. Conversely, insufficient water causes plants to conserve moisture by letting leaves yellow and drop. Establishing a consistent watering schedule that matches crepe myrtle’s needs can mitigate this.
Nutrient deficiencies, particularly nitrogen and iron, are common causes of yellowing leaves. A lack of nitrogen typically causes yellowing of older leaves, while iron deficiency leads to yellowing of younger leaves. This can be addressed by soil testing and applying the appropriate fertilizers or supplements such as nitrogen-rich fertilizer or iron chelate.
Pests like aphids, crepe myrtle bark scale, mites, whiteflies, scale insects, and mealybugs can affect crepe myrtles and cause yellowing and leaf drop. Aphids are a frequent pest that cause yellow and curled leaves through sap-sucking, which weakens the plant. Controlling aphids with insecticidal soap or neem oil is recommended to resolve this issue.
Crepe myrtle bark scale, a spreading pest, causes blackened limbs, stunted growth, and diminished flowering. While it does not kill the tree, it makes the tree unattractive and requires treatment to manage.
Fungal diseases like Cercospora leaf spot, Phyllosticta leaf spot, and Myrothecium leaf spot can cause yellowing and leaf drop in crepe myrtles. Fungicides can be used to manage fungal diseases affecting crepe myrtles.
Yellowing leaves in established crepe myrtles during spring and summer could indicate a nutrient deficiency, necessitating a soil test or controlled-release fertilizer application. In fall, yellowing leaves could signal a problem like disease or environmental stress. Inspect for diseases like bacterial leaf scorch and provide extra care during seasonal changes.
When newly planted or transplanted, crepe myrtles may experience transplant shock, manifesting as yellowing leaves. To mitigate transplant shock, provide consistent watering, full sun, and minimize stress by limiting fertilizer application until the tree shows signs of new growth.
Mulching helps maintain soil moisture and temperature, protecting crepe myrtle roots from environmental stress. It also aids in the prevention of weed growth and enhances the appearance of the garden.
In summary, addressing yellow leaves on crepe myrtles involves testing and amending soil nutrients, especially nitrogen and iron. Regularly inspecting for pests like aphids and crepe myrtle bark scale and treating with appropriate insecticides or organic controls is essential. Maintaining consistent watering, avoiding drought stress, and monitoring for diseases or soil pH imbalance and amending accordingly are crucial steps in maintaining the health and vibrancy of crepe myrtles.
A home-and-garden enthusiast tending to their home-and-garden may notice their crepe myrtle plants exhibiting yellow leaves, a common issue frequently encountered in this type of garden. To maintain the vibrant lifestyle that the stunning crepe myrtle blooms bring, gardening experts recommend regularly testing soil nutrients, especially nitrogen and iron, and addressing any deficiencies to prevent yellowing leaves.
