1, the environmental temperature of elm growth is too low, which leads to the appearance of physiological yellow leaves, while normal new leaves and old leaves appear alternately, and the yellow leaves are not obvious. If the temperature is too low in winter, it should be moved indoors for maintenance to improve the yellow leaf phenomenon.

2. The flowerpot is watered too much, and poor drainage will also cause the leaves to turn yellow. If this is the case, it is necessary to control the amount of watering in time and not to fertilize in the short term.

3. Too little light will make the leaves of elm bonsai yellow. To give enough light to solve the problem of yellow leaves, move the bonsai to the balcony and other places with sufficient light to maintain good indoor ventilation.

Extended data:

Bonsai protection

The molded elm bonsai should be planted in purple sand pots and other small pots for viewing before germination in spring, and should be planted in sandy soil with loose air permeability, good drainage and rich humus.

Elm has strong germination ability and fast growth, so it should be pruned frequently in the growing season, and the long and messy branches should be cut off to keep the tree beautiful. The best viewing period of elm bonsai is when New Ye Gang comes out. If all leaves are removed in early and middle August, water and fertilizer management should be strengthened in the later period.

By the end of September, new leaves will grow again to improve the ornamental value. In winter, move to a cool room with bright light, and even bury the flowerpot in the soil in the outdoor leeward and sunny place to reduce watering and make the plants fully dormant. When maintaining, turn over the pots every 2-3 years to make the bonsai grow vigorously and vigorously.