The Reasons and Solutions for Camellia Yellow Leaves
Camellias, as highly ornamental garden plants, often face the issue of yellowing leaves, which troubles many gardening enthusiasts. This article deeply analyzes the causes of yellow leaves from three dimensions: soil management, water control, and nutrient supply, and provides highly operable prevention and treatment solutions to help you quickly restore the plant's healthy state.
Analysis of the Four Core Causes of Camellia Yellow Leaves
Watering Imbalance Leading to Root Damage
Soil积水 is the primary culprit for yellowing leaves, as camellia roots begin to rot in an oxygen-deprived environment after 24 hours. By observing the characteristics of leaf yellowing, one can determine: when the bottom old leaves turn yellow first and water-stain spots appear at the leaf tips, it's time to stop watering immediately. It is recommended to use the bamboo stake test method—insert a bamboo stake into the potting soil for 2 hours, then pull it out; if the stake is moist, delay watering.
Soil pH Imbalance Affecting Nutrient Absorption
When the soil pH value is greater than 6.5, camellias exhibit typical iron deficiency chlorosis. It is suggested to test the pH value every quarter with pH test strips and adjust the pH by adding sulfur powder (50g per square meter) or decomposed pine needle soil. For potted plants, it is recommended to use a mixed soil formula: peat soil + decomposed leaf soil + perlite in a ratio of 5:3:2 to ensure good drainage and aeration.
Periodic Metabolic Phenomenon
During the seasonal transitions of spring and autumn, it is a normal physiological phenomenon for 5-10% of the lower leaves of the plant to naturally yellow. Maintenance should be maintained as usual during this time, and fallen leaves should be cleared to prevent the growth of pathogens. Be careful to distinguish from pathological yellow leaves: natural metabolic yellow leaves have uniform texture, no spots, and no rot on the petioles.
Methods for Diagnosing Nutrient Deficiencies
Lack of nitrogen is characterized by uniform greening loss throughout the plant, and a diluted soybean enzyme solution can be applied monthly. If new leaves show yellowing between the veins, iron chelate fertilizer should be supplemented; if the edges of old leaves are scorched, potassium should be supplemented. It is recommended to use special slow-release fertilizer for camellias, applying 30g per square meter for a sustained effect of 3 months.
Key Points for Implementing Systematic Prevention and Treatment
Establish a maintenance log to record watering frequency, fertilizing cycles, and other data; build a rain shelter during the rainy season to prevent water accumulation; and prune the roots when changing pots every two years. Use a thermometer and hygrometer to monitor the environment, maintaining humidity between 60-70% and temperature between 15-25°C for optimal growth.
Scientific maintenance requires grasping three golden periods: applying phosphorus fertilizer in the spring sprouting period to promote flower bud differentiation, spraying water in the morning and evening during the high-temperature summer period to cool down, and controlling water and fertilizer during the winter dormancy period. When yellowing occurs, follow the three-step approach of 'stopping watering, loosening soil, testing pH value, and supplementing the corresponding element,' usually 2-3 weeks for recovery.