Causes for Yellow Leaves
Bonsai trees require full time care. The most important aspects in growing and caring for your bonsai includes watering, humidity, lighting, temperature, fertilization, and air and soil circulation. If your bonsai is exhibiting yellow leaves, here are some common causes:
1) Natural Aging of the leaves: To make way for new growth from the leaf axils, the bonsai tree will naturally discard older leaves and develop a healthier set of new leaves. To promote new growth, make sure you moderate the watering, temperature and lighting of your tree.
2) Change of environment: The leaves of the bonsai will defoliate if their environment is changed. This typically occurs during transportation. The dropping of the leaves is the natural result of being in a low-light environment. It will take sometime for the bonsai to re-adapt to their new environment.
3) Watering: If the plant is not receiving enough moisture in the soil, the leaves of the bonsai will wither. To prevent root-dehydration make sure the watering of the bonsai is evenly distributed throughout the soil and the leaves. Do not allow the roots of your bonsai tree to become dried out.
4) Lighting: The bonsai should receive an adequate amount of lighting. A mixture of too much or too little light can cause the leaves of the bonsai to turn yellow or brown. The leaves require a sufficient amount of natural sunlight to allow for the process of photosynthesis. The best location is in a south or west-facing window that is un-shaded by buildings or trees. Refer to your particular tree for exact lighting requirements.
