Symptoms of overwatering orange trees generally appear because the orange tree cannot function properly due to excessive irrigation or because diminished vigor has led to a more severe disorder like a fungal infection. Observe and identify symptoms so you can assess any problem and treat the associated illness. To avoid symptoms of overwatering, give orange trees 1 inch or less of water a week and wait for the surface of soil to dry to "barely damp" before watering again.
Leaf Yellowing and Drop
The leaves of an orange tree may turn yellow or may drop from the tree prematurely. These problems are associated with a number of disorders due to overwatering. Because orange trees thrive in well-drained soil and are low water users, overwatering may create an area of standing water around the base of the tree. The yellow or fallen leaves may be a sign of foot rot, a fungal infection that attacks at the soil's surface; causing rot through the trunk and tissue that sends nutrients back and forth throughout the tree, leaves may no longer receive necessary nutrients and will turn colors or simply die and drop, according to the University of Florida IFAS Extension. Additionally, if the trunk is saturated with water, the orange tree cannot breathe as its supply of oxygen is gone.
Fruit Drop and Split
Fruit that drops from the tree or that splits while still attached to the branch is a common symptom of overwatering of orange trees. At the beginning of fall, if you notice the skin of your oranges splitting open, it's because orange trees absorb water quickly. When an absorbent tree receives too much water, it sends too much water to the fruit it bears. Excessive water forces its way into the fruit that has reached maturity; the skin is no longer expansive, so the pressure causes it to split apart. Rotting orange fruit or the presence of insects may be a secondary symptom brought on by the initial split. Due to decay and lack of appropriate nutrient content, fruit may also fall from the tree prematurely as a result of overwatering, according to the University of Florida IFAS Extension.
Abnormal Leaf Growth
When identifying different types of citrus trees, look to the color and size of leaves. Overwatering can cause the flow of nutrients to slow or cease, resulting in stunted growth of leaves or desaturated coloring. Abnormal leaf growth or other instances in which the orange tree is not developing at an appropriate pace is commonly associated with overwatering.
Though symptoms like cankers and leaf spots are signs of underlying disease, such as fungal infection, trees become more vulnerable to disease when improperly cared for. Vigorous trees are often capable of resisting or fighting off illness whereas trees in decline are highly susceptible to disease attack. While you may need to search for a control for a particular problem, the cause of the initial infection may simply be diminished health due to overwatering. Always check soil for standing water or soil that is more than damp between waterings.