What is Iron Chlorosis?

Iron deficiency chlorosis is a common problem in fruit trees and certain ornamental species in Winnipeg. Although Iron is an abundant trace element in soil, plants may have difficulty absorbing enough in high lime
or heavy clay soils. Other conditions which can induce iron deficiency include high soil pH (alkalinity), excess moisture, along with low soil temperatures.

Sign and Symptoms

The first symptom is a gradual yellowing of the tissue between the veins on leaves, while the veins themselves tend to stay green. If unchecked this condition may advance throughout the plant causing the tips and margins of some leaves to turn brown and become dry and brittle. Leaves may drop off the tree.

In severe cases, the leaves can become so chlorotic that they appear almost white. The leaf tissue is then so delicate that it easily scorches in the wind or sun. Often one branch of a single tree or perhaps a few
trees in an area may be affected. It is also possible to have an affected tree and a healthy tree of the same species growing side by side. In severe cases, entire trees can lose their leaves and die.

Control - What you need an arborist to do

Foliar Sprays

Younger and smaller plants are more receptive to spray treatments than older and larger ones . Leaves may be sprayed with an Iron Chelate mixture. If treatment is successful the plants
should begin to green up about 10 days after the application. Foliar applications are a temporary measure and successive treatment may be necessary.

Soil Application of Iron Chelates

Several treatments incorporating iron chelate in the soil are needed for large trees, often during a three year period, before the yellow leaf
condition disappears. With the most severely affected Maple or Birch tree it may take five years or longer.

Soil Amendment

Some iron is less available in soil with a high pH The addition of peat moss or the presence of decomposing organic matter may also improve Iron uptake. These methods are considerably less consistent than the use of Iron chelates.

**Iron chelate treatments should be done along with a regular fertilization program.**