Whats going on with my citrus tree - is it dying? What should I do?
It looks like Iron deficiency (iron chlorosis), Frank. This is a common problem and can cause serious problems to plant health and vigour.
Iron deficiency first appears as a ‘veiny’ look on new growth, with a darker green pigmentation retained on the leaf veins and the rest of the leaf developing a pale or yellowish green colour.
Iron is essential for healthy plant growth and disease resistance but can be lost from plants’ roots with excessive watering, long periods of rainfall and soil saturation, but the most common cause of iron deficiency is a high pH (or alkaline) soil.
Iron becomes soluble in water, and therefore available to plants, when the soil pH is acidic, or of a pH of 6 or lower. When the pH increases to 7 or higher, the iron in the soil solidifies and becomes ’locked up’ in the soil.
Some plants have a greater need for iron than others and will show symptoms of iron deficiency more quickly. These include azaleas, camellias, gardenias, hydrangeas, philodendrons, roses, citrus and fruit trees, many Australian native plants and lawns.
The usual method is to apply Iron Chelate. It can be applied to the leaves for quick uptake by the plant and also onto the soil. Iron chelate is iron in a form that is instantly available to the plant and will not ‘lock up’ in the soil, even if it has a high pH.
Repeat applications every few weeks may be advisable until the symptoms of iron deficiency disappear.