Skip Navigation

Iron Chlorosis

IRON CHLOROSIS
By Ken Mays 1988 Newsletter

Have you ever wondered why the leaves of some trees and shrubs turn yellow? It could be a number of reasons, but, the most common diagnosis is Iron Chlorosis.

“CHLOROSIS” is a condition caused by the loss of chlorophyll in the leaves. Chlorophyll is the pigment found in leaf cells which gives leaves their green color.

Iron Chlorosis can be the result of:

over-watering and poor drainage

high alkaline soils (pH of 6.7 – 8.5)

planting susceptible plants too close to concrete walks and foundations.

run off from copper down spouts and gutters.

Andromeda, azalea, Japanese holly, mountain laurel, rhododendron, pin oak, sweet gum…all are commonly affected. If these plants are in your landscape, you should watch for leaves that turn yellow and have pronounced “green” veins. If not corrected, new growth can become stunted and may result in premature death of the plant.

Powdered ferrous iron sulfate can be applied to soil beneath bedded plants showing these symptoms. The iron will be absorbed by the roots and, in time, help lower the pH. This treatment is automatically included in our “Broadcast Feeding” treatment. Foliar applications of Iron is most effective, however, drenching applications need to be performed every couple of weeks until the problem is corrected. Large trees showing signs of chlorosis are more efficiently treated through liquid soil injections applied during the summer months.

Soils with a high “Limestone” content tie up the iron and make it unavailable to the plant. When this occurs, applications of sulphur will expedite the movement of the iron in the soil to the plants’ roots.

As with insect or disease problems, iron chlorosis cannot be corrected with one application. Inspections by you and our technicians along with supplemental applications will reduce the chlorotic condition and bring back the green!