Citrus Tree Problems – Yellowing of Leaves.

Spanish Gardening Problems, Chlorosis in Citrus trees, yellowing of leaves

Chlorosis is the yellowing of leaf tissue due to a lack of chlorophyll. Chlorophyll gives the leaf its green colour and is necessary for the plant to produce the food it needs for its own growth, but requires the presence of minerals, particularly iron, manganese or zinc for this to take place..

There are many reasons why a plant may find it difficult to absorb the nutrients it needs to flourish;

   Poor drainage, ie a pot with no drainage holes

   Damaged roots after being transplanted, sometimes the tree may never recover from this

   Compacted roots as the plant may be in a pot that is too small for it

   Lack of nutrients, if the plant is confined within a pot and is not receiving mineral feed supplements

  Insufficient nutrients in the soil when planted in the ground.

Many members were shocked to find out that citrus trees need regular feeding throughout the year, with a rest period only during the hot summer months, and that trees in this area are particularly susceptible to chlorosis as the soil has a high lime content, which makes it very alkaline.

Iron becomes insoluble in soils with a high alkalinity, so it is difficult for the plant to absorb the nutrients it needs, the easiest solution being to feed with a citrus feed containing added iron and manganese.

If a plant has an iron deficiency, the younger leaves on fresh growth tips will normally turn yellow first, followed by the older leaves, whereas if the plant is suffering from manganese deficiency the older leaves will yellow first and progress outwards to the growth tips.

Antonio, our local Spanish expert, explained that before modern chemicals became available, the locals had always added manure to the soil to improve the mineral content around citrus trees,  particularly that of chickens, and that even today he uses no chemicals at all, putting all his coffee grounds around the base of the trees and having lush, healthy trees which produce fruit all year, around, a claim which was backed up by his neighbours.

He also stressed the need to water infrequently, but deeply, saying that trees on a drip system regularly fail to produce quality fruit with good flavour. He waters in a shallow circle around the tree, to the same spread as the branches of the tree, and allows the soil to dry out completely before re-watering, too much water being just as bad for citrus trees as too little, leaf loss , yellow leaves and sudden death being symptons of waterlogged roots.

Other Citrus Maintenance Jobs to do now.

-         Remove any oranges left on the trees as new blossom forms, clear away rotten fruits, spent leaves and weeds from the base of the trees, and prepare the irrigation circles before the ground bakes.

-         It’s still not too late to cut out the suckers; tall, upright shoots coming from the centre of the tree, which distort the shape and sap the energy from fruit producing branches.