Leaves falling off lemon trees is a common phenomenon, and there are several potential causes. Contrarily to popular belief, it is not always indicative of a sick tree. It is, instead, often simply a natural process of tree development. Such processes start from the top of the tree because that is where the oldest leaves have been growing for the longest. The following paragraphs will focus on why lemon trees shed their leaves, as well as when and how.
Environmental Factors
As a short-term process, lemon tree leaves can fall off due to environmental influences. Heat, for example, causes faster evaporation of a tree’s water reserves, drying out the leaves more quickly than other seasons. Additionally, over-fertilization can cause leaves to turn yellow and drop off. In cold winter months, the frostbite could damage the leaves as well as the bark. Too much sunlight can be inconvenient too.
Dormancy
Another common factor is dormancy, a season when the trees slow or stop growing, or else simply draw their nutrients inward. At this point, the lemon tree will often shed its oldest and most vulnerable leaves. Such shedding helps protect the remaining leaves during the dormant season, while also preparing the tree for a burst of growth with the new season.
Aging
A third common factor in a lemon tree losing its leaves is the aging of the plant itself. As a tree ages, it can no longer sustain its internal support system, causing it to shed more leaves than it can sustain. Most often, this is seen in the trees oldest and weakest leaves. In such cases, it’s best to make sure the tree has the appropriate nutrients and environment to allow for continued growth.
Pest Infestations
Pests can cause leaves to drop, by attacking the stem and leaves of the tree. Aphids, for instance, prefer young, tender leaves with higher nitrogen content, while citrus whitefly prefer older, tougher leaves. By targeting these areas of the tree, the pests cause the leaves to drop, providing them access to even more food. If a lemon tree is losing its leaves, proper pest identification and treatment is needed before further damage is done.
Disease
Lemon trees can also lose their leaves due to disease, such as citrus canker or citrumovirus. These diseases, though different in how they manifest and how they are treated, both cause leaves to turn yellow, dry out, and eventually fall off. Treatment must begin quickly to prevent the spread of the disease throughout the tree. If the disease is more advanced, removal of the tree may be necessary.
Transplant Shock
Finally, transplant shock can cause a lemon tree to drop its leaves. Transplant shock is the result of the disturbance of the root system due to replanting or the movement of a tree. During this time, the tree may lose some or all of its leaves, as the process of regrowing can be harmful to the tree. This can be especially true when a tree is moved without being properly prepared. Proper watering and fertilization can help reduce and speed up the effects of transplant shock.
Fertilizing and Watering
When a lemon tree is losing its leaves, proper fertilizing and watering can help to reduce the affects of the aging process or disease. Applying fertilizer and ensuring the proper amount of water is given can help the tree to regain its strength and minimize the affect of environmental factors. Additionally, proper pruning can help to speed up the growth of the new healthy leaves, while also providing access to more light and water for the tree.
Insecticides and Other Treatments
In cases of pest infestations, chemical insecticides can be used to treat the lemon tree. Insecticides should be used sparingly and with proper precautions to avoid excess damage to the tree. Additionally, there are biological controls available, such as natural predators or natural pesticides. Such treatments can help to reduce the pest population without harming the tree or the environment.
Physical Removal of Leaves
In some cases, it may be necessary to physically remove leaves or branches in order to save the lemon tree. Pruning can help to reduce the workload of the tree, allowing it to gain strength and create healthier leaves. In extreme cases, removing large portions of the tree may be necessary to save it. In such cases, it is best to enlist the help of a professional who can help to reduce the damage done to the tree.
Compost Utilization
Finally, composting can be used to help recycle the fallen leaves of the lemon tree. Composting can be used to make new soil, which can then be used to nourish the tree or other plants in the garden. Such composting not only helps to reduce the amount of waste, but can also provide additional nutrients to the garden.
Growth Regulation
Regulating growth is a key factor when it comes to a lemon tree that is losing its leaves. Proper pruning of the tree can reduce the amount of leaves it has to sustain, while also preventing overgrowth that could lead to further problems with the tree. Additionally, proper spacing between the branches will allow for better light and air circulation.
Light and Air Circulation
Proper light and air circulation are essential for the health of the lemon tree. Too little air circulation can cause leaves to yellow, dry out, and fall off. Additionally, proper pruning of the tree, to provide better light and air circulation, can help to reduce the amount of leaves the tree has to sustain. By managing these two factors, the tree can be better equipped to maintain healthy and strong leaves.
Nutrient Requirements
A lemon tree needs the proper amount of nutrients in order to produce healthy leaves. Nutrients such as nitrogen, phosphorus and potassium are essential for the tree, and can be provided by using fertilizer or compost. Additionally, proper trimming and pruning can be used to help the tree expend its energy more efficiently, while also encouraging the growth of new healthy leaves.
Disease Prevention
Finally, it is important to be mindful of any potential diseases that could harm the tree. Citrus canker and citrumovirus are two of the most common, and should be treated quickly if found. Additionally, it is important to protect the tree from pests, as such can cause serious damage to the tree and its leaves.
