Why Do Lemon Trees Lose Their Leaves Suddenly?

by Molly Allman Google
    Lemon trees have a low heat requirement, which means they can grow in areas where grapefruit and oranges cannot.


    Lemon trees (Citrus limonia) are thorny evergreen citrus trees with narrowly ovate light green leaves and purplish-tinted white flowers. The tree produces yellow lemons pointed at both ends, which contain an acidic juice. Lemon trees thrive in areas of low frost, such as regions that fall within U.S. Department of Agriculture hardiness zones 9A through 11. While some leaf drop during winter and early spring is normal, there are several reasons for heavy leaf drop on lemon trees, including improper care, disease and fungi.

    Nutrient Deficiency

    In lemon trees deficient in certain key nutrients, such as magnesium and iron, leaf drop can occur. Symptoms of magnesium deficiency include yellowing or bronzing of leaves, and in severe cases leaves drop freely. Symptoms of iron deficiency include thin, small leaves that suffer from chlorosis and drop early. Applying Epsom salt to the soil can help with magnesium deficiency, and iron by apply iron chelates. Iron deficiency occurs most often in trees with inadequate irrigation or growing in areas with poor drainage.

    Excessive Fertilization

    Too much fertilizer can lead to leaf drop. Young trees require light fertilization during the first year; about 1 tablespoon per month during spring and summer. Beyond the first year, fertilize trees once every four to six weeks and gradually increase the amount of fertilizer each year as the tree grows, using a fertilizer made for citrus or an 8-8-8 fertilizer. When using fertilizer, sprinkle it evenly, covering the entire root zone. Do not pile fertilizer right at the tree base, as this can cause damage. Proper fertilization practice can help prevent leaf drop from over-fertilization.


    Certain insect pests can cause leaf drop on lemon trees. California red scale is a type of armored scale that lemon trees are susceptible to. The scale can cause yellowing of leaves and leaf drop. The pests are most active in late summer and early fall. To control California red scale, you can introduce natural predators, such as parasitic wasps.

    Root Rot

    Phytophthora root rot often affects lemon trees and causes many symptoms, such as yellowing of leaves and leaf drop. This fungus affects the root system of the lemon tree and is often caused when the trunk remains wet. To avoid root rot, plant trees in areas with good drainage and where they will not receive frequent irrigation. Reducing irrigation can help if done before root rot becomes severe; if damage is severe, you should remove the tree and fumigate the area.

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