Lemon tree leaves can yellow for a variety of reasons, with some of the most common being improper watering, disease, nutritional deficiencies and sunburn. The first step to reversing the yellowing of a lemon tree’s leaves lies in understanding the cause.
Lemon tree leaves may yellow if their soil is not watered effectively or if too much or too little water is used. As a general rule, if the soil is dry, it needs to be watered. wilted leaves may indicate a lack of moisture; a sign that it’s time to water. Over-watering a lemon tree can also cause yellowing, as it deprives the roots of the oxygen they need in order to absorb water and other vital nutrients from the soil.
Exposing a lemon tree to too much sunlight may also cause its leaves to yellow. Sunburned lemon tree leaves, in addition to yellowing, may exhibit spots and discoloration. This can be prevented by ensuring the lemon tree stays in an area that gets indirect sunlight, or by providing it with appropriate shading.
Nutritional deficiencies can also be a factor in the yellowing of a lemon tree’s leaves. If a nutrient deficiency is present, the leaves may yellow around their veins and show other signs of distress. Regular fertilization can help ensure the tree is receiving the necessary nutrients for its healthy growth.
Disease can also be the cause of lemon tree yellowing. Common signs of disease-related yellowing of the leaves include yellowing of their tips, discoloration and leaf drops. One of the most common disease-causing agents is citrus greening; a bacterial infection that can be treated by removing the infected leaves.
Inadequate lighting can also lead to yellowing of lemon tree leaves. If a lemon tree isn’t receiving enough light, its leaves may yellow and dry out due to the lack of photosynthesis. An indoor lemon tree can be moved to a spot that receives more natural light, while an outdoor tree may need to be pruned or otherwise adjusted in order to receive more light.
Another potential cause of yellowing lemon tree leaves is an insect infestation. Infestations of scale insects and aphids may cause yellowing of the leaves, as well as curling, spots or other discoloration. The infestation can be controlled with an organic pesticide or by removing the affected leaves.
Environmental factors like air pollution, herbicides and fertilizers drift can also affect the yellowing of a lemon tree’s leaves. Areas with higher concentrations of air pollution may cause yellowing of the leaves due to the buildup of toxins in the air. Incorrect application of herbicides and fertilizers may also lead to yellowing.
Lemon trees require well-draining soil in order to thrive. Poor drainage will cause excessive buildup of salts and minerals, preventing the lemon tree’s roots from obtaining the nutrients they need. Over time, this can lead to yellowing of the leaves, wilting of their edges, and leaf drop.
Pests & Pathogens
The presence of pests and pathogens can inhibit a lemon tree’s growth and affect its appearance. Aphids, mealybugs, and citrus whitefly can all cause yellowing of the tree’s leaves. Pathogens and diseases, like citrus canker, citrus greening and gummosis, can also be responsible for the yellowing of leaves, as well as discoloration, spots, and other signs of distress.
Sometimes, improper pruning or too much pruning can cause yellowing of a lemon tree’s leaves. Pruning a lemon tree too much can lead to too much foliage being removed, resulting in the tree being unable to produce enough energy to properly photosynthesize. This can cause the tree to undergo yellow leafing in order to conserve energy.
The use of chemical pesticides, fungicides and herbicides can also be responsible for yellowing of the leaves. If these chemicals are used too frequently or in excessive quantities, they can burn the leaves and cause yellowing, spots, and other signs of damage. To avoid this, it’s best to use organic pesticides, fungicides and herbicides, or to contact a professional for assistance.