- Yellowing leaves
- Dark green veins
- Premature leaf drop
Iron chlorosis is a very common nutrient deficiency that is seen in many trees and shrubs growing under higher pH soil conditions (greater than pH 6.5). Leaves become pale green to yellow, and leaf veins are a darker green. On hot, sunny days the leaf margins can scorch and leaves drop prematurely.
Iron chlorosis is the result of a lack of iron in the soil available to the plant. Alkaline soils with a high pH increase the chances of a plant developing iron chlorosis. Though iron deficiency is more common, this problem can occur in conjunction with manganese deficiency and cause similar symptoms. A soil test is needed to conclusively diagnose this problem.
The management of iron chlorosis is both difficult and expensive, so prevention through the selection of more tolerant plant species and cultivars is essential. Always check soil pH and submit a leaf sample for analysis. See the links section (the i in the upper left corner of the main page of this app) for a plant diagnostic lab in your state. There are several treatments for the management of iron chlorosis, but these need to be continued on a regular basis and most people find them unsatisfactory in the long-term. Foliar sprays of iron can temporarily remove symptoms, but must be applied repeatedly. Application of trunk injections by professionals can also reduce symptoms temporarily but can cause injury. For large trees, soil treatment is usually unsuccessful due to the tremendous capacity of soil to buffer its pH, and therefore is not recommended.
Pesticides are neither available nor recommended for managing this condition.
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