Lemon trees are not deciduous; they are evergreen plants. This means the trees retain their foliage throughout the year, maintaining a green canopy even through the winter months. Like all citrus, lemon trees belong to the genus Citrus, which is comprised entirely of evergreen species. This characteristic influences the tree’s physiology and its year-round cultivation requirements.
Understanding Deciduous and Evergreen Classifications
The distinction between deciduous and evergreen trees relates to their strategy for managing unfavorable environmental conditions. Deciduous plants, such as maples and oaks, undergo a synchronized leaf drop, shedding all their leaves, typically in the autumn. This seasonal defoliation allows the tree to enter a state of dormancy, minimizing water loss and conserving energy during cold winters or prolonged dry periods.
Evergreen plants keep their leaves for longer than one growing season, allowing them to continue performing photosynthesis whenever conditions permit. This strategy is effective in climates that do not experience harsh or prolonged periods of freezing or drought. While evergreen trees do shed leaves, this process is gradual and asynchronous. The continuous presence of green leaves allows for immediate energy production.
How Lemon Trees Manage Leaf Replacement
Although lemon trees are evergreen, individual leaves are shed in a constant, staggered replacement process. The typical lifespan of a lemon tree leaf ranges from 12 to 18 months before it drops. This continuous turnover ensures that the tree maintains a photosynthetically active canopy without the dramatic seasonal change seen in deciduous species.
The shedding of old leaves often coincides with the tree’s periodic growth spurts, known as flushes, which commonly occur in the spring and sometimes in the autumn. Before dropping, the tree reclaims valuable nutrients from the aging leaf, causing it to turn yellow. New leaves quickly emerge to replace the lost foliage, sustaining the tree’s ability to produce sugars. The thick, waxy cuticle covering the leaves effectively reduces water loss through transpiration, supporting year-round foliage retention.
Caring for Evergreen Citrus Trees
The evergreen nature of lemon trees dictates a specific approach to their cultivation and care, particularly concerning cold protection, watering, and nutrient supply. Because lemon trees do not enter a deep dormant state, they remain susceptible to freezing temperatures. Any cold snap can damage leaves, branches, or even the entire tree, especially when the root zone temperature drops below 50 degrees Fahrenheit. Protecting the tree from frost is a necessary year-round consideration in marginal climates.
Water management must be consistent since the tree’s continuous photosynthesis demands a steady supply of moisture. Unlike deciduous trees that halt most water uptake in winter, lemon trees require regular, deep watering even during cooler months, although the frequency can be reduced. Allowing the soil to dry out excessively can cause the tree to drop leaves as a stress response to conserve water.
Citrus trees are heavy feeders and require a fertilization program to support their ongoing growth flushes and fruit production. Growers typically apply fertilizer multiple times a year, often splitting the total annual dose into two or three applications. The final feeding is often recommended later in the season, around August or September, to support the tree’s continuous production cycle.