At a time in the season when you expect your landscape to be at its greenest, many area trees are yellow and already starting to drop leaves.This yellowing of normally green leaves is due to a lack of chlorophyll, a condition known as chlorosis. Chlorophyll is responsible for the green color of leaves and is essential for the tree to produce the food it needs to sustain growth and maintain health. Chlorotic leaves are by contrast pale green, yellow or yellow white.
As the chlorosis advances, clusters of leaves will take on a scorched look. Chlorosis may show up on one or two branches or the whole tree may be affected. Many factors, individually or in combination contribute to chlorosis. These involve nutrient deficiencies that are directly related to the soil your trees are planted in, including over watering and poor drainage, the use of plastic sheeting as a mulch, heavy, compacted clay soil and high (alkaline) soil Remedies for chlorosis include applying iron supplements in a form the tree can use, as well as improving soil structure and reducing soil