Meyer lemon trees offer fragrant blossoms and delicious fruit. However, leaf shedding can signal underlying stress or imbalances in the tree’s environment or care. Understanding these reasons is the first step toward restoring your tree’s health.
Environmental Factors Leading to Leaf Drop
Meyer lemon trees are sensitive to their surroundings. Environmental stressors frequently cause leaf loss, leading to visible signs of distress like yellowing or browning leaves before they drop.
Watering Imbalances
Inconsistent watering is a leading cause of leaf drop. Both overwatering and underwatering severely impact tree health. Overwatering often leads to root rot, where roots become waterlogged and deprived of oxygen, causing leaves to yellow and drop. Underwatering results in crispy, dry leaves that fall off as the tree struggles to hydrate. Check the soil by inserting your finger two inches deep; water only when the top layer feels dry. Ensure the pot has adequate drainage holes.
Light Stress
Meyer lemon trees require at least eight hours of direct sunlight daily. Insufficient light weakens the tree, leading to pale leaves that drop. A sudden change in light, such as moving a tree from shade to intense sun, can cause leaf scorch and drop. Acclimatize your tree gradually to new light levels to prevent shock. Indoors, a south-facing window is ideal, and supplemental grow lights can help during darker months.
Temperature Fluctuations
Meyer lemon trees prefer stable temperatures, typically 50-80°F (10-27°C). Sudden temperature drops, cold drafts, or extreme heat induce stress and leaf loss. Temperatures below 50°F can cause damage, and prolonged exposure below 29°F can be fatal. Protect your tree from sudden temperature shifts, especially when moving it indoors or outdoors.
Humidity Levels
Meyer lemon trees prefer higher humidity, ideally 50-60%. Low indoor humidity can cause leaves to dry, curl, and drop. To increase humidity, place the pot on a pebble tray filled with water, ensuring the pot does not sit in standing water. Misting leaves or using a small room humidifier can also help.
Nutritional Issues and Soil Health
Nutrients and soil condition significantly impact a Meyer lemon tree’s health and leaf retention. A balanced diet and appropriate soil chemistry are fundamental for robust growth. Problems in these areas often manifest as discolored or dropping leaves.
Nutrient Deficiencies
Meyer lemon trees are heavy feeders and can develop nutrient deficiencies leading to leaf discoloration and drop.
Common Deficiencies:
Nitrogen deficiency: Older leaves turn uniformly pale green to yellow.
Iron deficiency: New leaves yellow while veins remain green (interveinal chlorosis).
Magnesium deficiency: Yellowing starts at leaf edges, leaving an inverted V-shaped green area near the midrib of older leaves.
Use a balanced, citrus-specific fertilizer during the growing season to prevent these issues.
Incorrect Soil pH
Soil pH directly influences nutrient absorption. Meyer lemon trees thrive in slightly acidic soil (pH 5.5-6.5). If pH is too high (alkaline), essential micronutrients like iron, manganese, zinc become unavailable, leading to deficiency symptoms and leaf drop. Regularly test soil pH with a home kit. Adjustments can be made by adding sulfur to lower pH or lime to raise it.
Pests and Diseases as Causes
Pests and diseases can cause Meyer lemon tree leaf drop. Early identification of these threats is important for effective treatment and preventing widespread damage.
Common Pests
Common pests that cause leaf drop include:
Spider mites: Tiny arachnids that feed on leaf sap, causing yellowing, splotchy leaves. Look for fine webbing.
Scale insects: Small, stationary bumps on stems and leaves that suck sap, causing yellowing and leaf loss.
Mealybugs and aphids: Sap-sucking insects that deform new growth and cause leaf drop.
Treat with horticultural oil, insecticidal soap, or neem oil, applied to both top and undersides of leaves.
Disease Identification
Diseases can contribute to leaf drop, often with other symptoms.
Common Diseases:
Root rot: Caused by overwatering, roots decay, leading to yellowing leaves and drop.
Anthracnose: A fungal disease causing leaves to shrivel, turn dark, and drop prematurely.
Citrus scab: Manifests as wart-like lesions on leaves and fruit, potentially leading to leaf distortion and drop.
Proper watering, adequate air circulation, and overall tree health prevent many diseases. Fungicides may be necessary for specific fungal issues, but proper diagnosis is important.
Other Causes and Prevention
Other situations can also lead to Meyer lemon tree leaf drop. Recognizing these causes helps in providing comprehensive care.
Transplant Shock
Moving or repotting a Meyer lemon tree can cause transplant shock, resulting in temporary leaf drop. This happens as the tree adjusts to new conditions and its root system is disrupted. To minimize shock, disturb roots as little as possible during transplanting and water immediately afterward. Partial shade after moving can help the tree acclimate.
Natural Leaf Shedding
Some leaf drop is a normal part of a Meyer lemon tree’s life cycle. As evergreens, they don’t shed all leaves seasonally like deciduous trees, but older leaves naturally yellow and fall off. This minor, gradual shedding, especially of older foliage, is generally not a concern. Distinguish this natural process from significant, rapid leaf loss due to stress.
General Care for Prevention
Maintaining a healthy Meyer lemon tree involves consistent monitoring and proactive care. Regularly inspect your tree for early signs of pests, diseases, or nutritional deficiencies for prompt intervention. Consistent watering, adequate light, stable temperatures, humidity, proper fertilization, and correct soil pH support the tree’s vigor and resilience.