Reasons for blackening of the leaves at the bottom of rhododendron. Prevention and control measures for blackening of the leaves at the bottom of rhododendron. As a traditional ornamental flower in China, Azalea is deeply loved by people for its unique color and attitude. During daily maintenance, many flower friends will encounter the problem of blackening of the leaves at the bottom of rhododendron, which not only affects the ornamental value of rhododendron, but may also threaten its growth and health. This article will provide you with a detailed analysis of the reasons for blackening of the leaves at the bottom of rhododendron and the prevention and control measures. Help you easily deal with this maintenance challenge. Reasons for blackening of the bottom leaves of rhododendron 1. The most common reason for infection by bacteria The most common reason for blackening of the bottom leaves of rhododendron is bacterial infection, such as leaf spot disease, root rot, etc. These bacteria will invade the leaves of rhododendron under appropriate conditions, causing the leaves to black and withered.
2. Improper water management If too much or too little watering will cause the bottom leaves of rhododendrons to turn black. If too much watering will cause the roots to lack oxygen and cause the roots to rot; if too little watering will dry the soil and lose water in the leaves, which will cause the leaves to turn black.
3. Rhododendron prefers semi-shaded environments with insufficient light. If it is in an environment with insufficient light for a long time, leaf photosynthesis will be weakened and resistance will be reduced, which will easily cause diseases and cause blackening of the bottom leaves.
4. Poor soil quality. Poor soil, poor air permeability, poor drainage, etc. will lead to blackening of the bottom leaves of rhododendrons. Excessive accumulation of harmful substances in the soil will also cause damage to rhododendrons. Prevention and control measures for blackening of the bottom leaves of rhododendron 1. Prevention and control of bacterial infections (1) Remove diseased leaves in time to reduce the spread of bacteria;(2) Reasonably apply fertilizer to enhance rhododendron's disease resistance;(3) Use fungicides to control, such as Bordeaux liquid, mancozeb, etc.
2. Water management (1) Master watering time to avoid too much or too little watering;(2) Maintain soil permeability to avoid hypoxia in roots;(3) Reasonable pruning to reduce leaf moisture evaporation.
3. Light adjustment (1) Place the rhododendron in a semi-shaded environment to avoid direct sunlight;(2) Regularly adjust the position of the rhododendron to ensure that it receives even light.
4. Soil improvement (1) Select soil with good air permeability and strong drainage;(2) Regularly replace the soil to avoid the accumulation of harmful substances;(3) Add organic fertilizers to improve soil fertility.
Blackening of the bottom leaves of rhododendrons is a common problem during rhododendrons maintenance. Understanding its causes and prevention measures is crucial to maintaining the healthy growth of rhododendrons. I hope this article can help you and make your rhododendrons full of vitality.
References: [1] Zhang Wei, Research on the Control Technology of Rhododendron Diseases [J], Plant Protection, 2016, 42 (4): 78-81.
[2]Wang Xiaofang, Research on Soil Improvement and Conservation Technology of Rhododendron [J], Horticulture, 2018, 35 (1): 56-58.
[3]Li Ming, Causes of blackening of bottom leaves of rhododendron and control measures [J], Flowers, 2019, 30 (3): 45-47.