Chlorosis- a condition in which leaves turn yellow with veins remaining somewhat green.
Above on the left is a chlorotic citrus tree with yellowing leaves and some curling of the leaves.
Above on the right is a healthy citrus with good looking green leaves- lots of them.
In our area we have a lot of heavy clay and alkaline soils which tie up nutrients to trees and plants. In this case some of my Citrus are showing these signs of chlorosis or the lack of available iron. Sometimes a lack of zinc or manganese can also cause this. Believe it or not the healthy tree is in the same garden but is planted in better soil where the bunny hutch used to be!
The extra organic matter helped to loosen and fertilize the soil so that tree is doing great.
For the other trees I am using 'liquinox' chelated iron and zinc (in liquid form) diluted in a
bucket of water and then fed around the drip line of the trees. This is done every 3 months in the growing season. Our large Orange tree I will give several buckets full around the much bigger drip line.
This should help the trees green up, fruit better and be more full. It is a good idea to add compost or mulch around the base of chlorotic plants and carefully work it in if you can. This will break the heavy clay surface and allow nutrients to penetrate the soil. Try not to break up the root mass too much. For citrus it is important for the leaves to shade the thin bark or the branches and trunk can get sun scald. So the fuller the canopy the better.
Citrus are just one of the trees effected by this condition. Gardenias are also especially susceptible along with Hibiscus, Avocado, Azaleas and Rhododendrons. Nutrient deficiency can effect any plant but these are some that are prone to iron deficiency in our area.