It is a common misconception that lemon trees lose their leaves in winter. While other deciduous trees, such as oak and elm, do drop their leaves as a response to changing temperatures, lemon trees retain their foliage. Lemons can be grown in USDA hardiness zones eight through 10, where temperatures rarely dip below freezing and are typically range from 45° to 85° degrees Fahrenheit. As a result, lemon trees don’t need to shed their leaves in order to survive the winter.
An alternate reason why lemon trees don’t lose their leaves in winter is because losing leaves is an energy intensive process. With the cool temperatures of winter, lemon trees enter a dormancy state and don’t expend much energy at all. Therefore, they don’t need to replace their leaves as they would if they were growing in warmer climates.
Lemon trees can drop their leaves at other times, however. One instance is if a lemon tree gets too much nitrogen fertilizer in its soil. When this occurs, the tree will grow more foliage than it needs, causing it to shed some. This type of leaf shedding is usually only happens in certain areas, such as Southern California, where lemon trees are grown in abundance.
Furthermore, lemon trees may also experience a situation where they drop their leaves due to disease. When a lemon tree gets a disease like root rot, it can’t absorb enough water and nutrients from the soil, causing it to drop its leaves. Another common symptom of root rot is stunted growth, wherein the tree doesn’t reach its normal size or yield.
Finally, lemon trees may also lose their leaves due to environmental stress. If a lemon tree is grown in an area that is too cold – or too hot – its foliage may fall off as a result. It’s important to make sure that your lemon tree is in an area with the right temperature range, as well as the right amount of water and nutrients to prevent this type of leaf shedding.
Heat Stress
Heat stress can also be a factor when it comes to does a lemon tree lose its leaves in winter. Extreme heat can cause lemon tree leaves to become stressed and eventually drop off from the tree. The primary concern is that these leaves will retain too much water, thereby causing them to swell, become tender and eventually fall off. In areas that receive excessive heat, such as the Southwestern US, lemon trees require extra protection for their leaves to ensure they don’t succumb to heat stress.
Protection from extreme weather conditions can come in several forms, from planting lemon trees in an area that offers some shade during the hottest parts of the day, to using blankets or even fans to keep their foliage cooled. Additionally, the application of mulch helps to minimize the soil temperature and keep roots cooler. Finally, the addition of adequate water in the soil, coupled with lighter fertilizer applications, also can help reduce the risks of heat-related leaf loss.
Water Stress
Along with heat stress, water stress can also contribute to a lemon tree losing its leaves. Without adequate water and nutrients in the soil, leaves may suffer and fall off. This can happen in the summer months, especially if rain patterns are abnormal or the soil is too sandy, making it difficult for the lemon tree to absorb enough moisture.
When it comes to watering, lemon trees should be watered deeply (but not excessively) and allowed the soil to dry out between waterings – ideally to a depth of about one inch. A good rule of thumb is that one inch of water per week is adequate for most lemon trees. Additionally, applying mulch around the base of the tree helps to conserve moisture in the soil and regulate soil temperatures, aiding in protecting the lemon leaves.
Nutrient Deficiencies
In addition to heat and water stress, nutrient deficiencies can also cause lemon leaves to fall off suddenly. Under normal circumstances, a lemon tree needs essential nutrients such as nitrogen, phosphorus and potassium to thrive. If there is a deficiency in any of these, or other, essential nutrients, lemon trees may experience leaf drop.
For this reason, it is important to use soil tests to determine the nutrient levels of the soil before planting a lemon tree, and then to regularly supplement the soil with the necessary nutrients. Additionally, regular applications of compost or composted manure help to both improve the soil structure and bring in additional nutrients for the tree’s foliage.
Environmental Factors
Finally, environmental factors such as wind, cold and air pollution can contribute to lemon trees losing their leaves in some cases. In areas with strong or persistent winds, leaves can be damaged or broken off, making it more difficult for the tree to substitute them. Cold drafts can also cause leaves to become weak or brittle, causing them to break off or fall prematurely. Air pollution can also have an adverse effect on lemon tree leaves, causing yellowing and eventual leaf drop.
When it comes to protecting lemon trees from wind, cold and air pollution, the best thing that can be done is to avoid planting them in areas where these forces converge. Additionally, fences and walls can be erected to provide a physical barrier from these sources, and some trees may require winter protection from the cold (such as burlap wrap). Finally, decreasing air pollution is important for any type of tree, so avoiding the burning of fuels and planting more trees are steps that can be taken in order to reduce this type of damage.
