What Causes Azaleas To Turn Yellow. 01072016 The condition you probably see is called chlorosis This simply means an abnormally yellow color of plant tissues. Leaves turn light green to yellow then creamy white between the veins while the veins remain green.
Youngestnewest leaves become chlorotic pale green. While there is currently nothing available to control stunt nematodes on azaleas with proper fertility and watering practices the plants are better able to tolerate attacks. Chlorosis is usually caused by the soil pH being too high making iron unavailable to plants.
For azaleas a decidedly acid-loving plant a serious iron deficiency caused by the pH of the soil being too alkaline can bring on chlorosis.
Yates Leaf Greener Iron Chelate. Use a soil applied iron fertilizer at the labeled rate. Azalea leaves naturally turn these colors before they fall. This is because Iron is more available at a lower pH and as the soil pH increases it becomes less available.