Whether it’s an indoor tropical bonsai basking in a warm, greenhouse-like climate or a deciduous outdoor variety that embraces the seasons, understanding your tree’s needs and responding to them promptly is the key to its longevity. However, sometimes even the most devoted Bonsai-ka can run into challenges with their prized miniatures.
If your bonsai is losing leaves, check its cambium layer – the thin growing surface in trunks, branches and roots that indicates life. The cambium should be green in color. If it’s brown, your plant is dead.
Leaf dropping is a common reaction to stress, such as an overly hot room or a sudden change in the weather. It’s a survival mechanism honed through evolution to cut excess baggage and conserve energy in times of hardship.
Other signs of stress include a yellowing or shriveling of leaves, brown leaves, and root rot. Inconsistent watering, soil that’s too dense or poorly drained, and pests can also contribute to leaf drop.
When it’s time to repot your plant, be sure to use a well-draining potting mix designed specifically for Bonsai. If your soil is extremely dense, it can block oxygen and promote rot while creating an ideal environment for pests. Then, when you do water your plant, water thoroughly so the top layer of the soil is damp but not soaking wet. Likewise, overwatering can cause damage to the roots by drowning them or causing them to swell up and die.