Treating Iron Chlorosis in the Fall

 

You see them all over the city. Instead of a healthy, rich green, the leaves of trees as well as some shrubs look light green to yellow with prominent veins. Many leaves have a scorched appearance.

This yellowing of normally green leaves is due to a lack of chlorophyll, brought on because the tree involved is lacking the micronutrient Iron. The root cause of iron deficiency is directly related to the quality of the soil your trees and shrubs are planted in. Remedies for iron chlorosis include applying iron supplements in a form the tree can use, as well as improving soil structure, reducing soil pH and building stronger root systems. 

It's called iron chlorosis and as 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. 

Remedies for chlorosis include applying iron supplements in a form the tree can use, as well as improving soil structure and reducing the pH of the soil.

Iron supplements are available in liquid and granular forms. Chelated iron is not affected by soil pH levels and is more readily available to your trees. 

The best iron supplement choice is a complex of iron and the chelating agent EDDEHA.

These supplements can be applied directly to the soil under the tree; through a series of holes drilled around the drip line or through a soil injection needle, like this one.

The method selected depends on where the tree is planted in your landscape.

Applying organic materials such as compost, peat moss and humate will improve soil structure and reduce alkalinity. Each of these products is applied to the area under the dripline, three to four times per year. 

Humate is a chelating agent, so it helps trees absorb existing iron. It is sold as ferti-lome HuMic. Put the HuMic down first and water it in.

Follow this step with a thin (1/8" to ¼") layer of Sheep and Peat or Peat Moss and water in thoroughly. If your tree is surrounded by mulch, you can pull the mulch back past the drip line and follow the same process as above: HuMic, then Sheep and Peat or Peat Moss and water in. 

An alternative approach is to drill a series of holes twelve to eighteen inches apart, eight to ten inches deep around the drip line and fill each hole with HuMic and Sheep and Peat and then water in. Repeated applications will improve the soil structure, increase microbial activity and encourage the tree to take up more iron on its own. 

Your tree cannot overcome chlorosis on its own.  Understanding and resolving iron chlorosis is complex. We encourage you to stop by the store with a sample of your tree. We’ll verify the problem and help you select the right products to help restore your tree’s health.