Normal Growth Patterns
Like many other plants, bamboo does most of its growing in spring and summer. Unlike other plants, however, this is also when bamboo tends to lose leaves. This normal pattern of leaf loss can easily be mistaken for a problem and inexperienced gardeners often think the plant needs more water. Over-watering is the most common way to kill bamboo plants, so it’s important to recognize normal leaf drop.
Too Much Water
Excess water in the soil means there is too little oxygen. Bamboo must have soil that drains well to prevent soggy soil. A bamboo that is too wet will begin to develop brown leaf tips. Eventually the whole leaf will turn brown and drop. Leaves may also curl under. The roots may also turn black or emit an odor. Check the soil – if it’s soggy, your bamboo is too wet.
Too Little Water
Although some bamboo can handle a little drought – depending on the variety – it is not a desert plant. Hot weather and dry winds are particularly hard on the plant. Bamboo leaves roll inward if too dry. If the leaves return to normal after watering, this is a good sign that this is lack of water. If the water shortage persists, the plant will begin to drop leaves.
Bamboo in Containers
Bamboo in containers requires special management and attention. For these plants:
- Choose a large enough pot with adequate drainage.
- Select soil that is moisture-retentive but also drains well.
- Check soil daily; water if top inch is dry.
- Water heavily every few months and let drain completely to leach salts from soil.
Many bamboo varieties can be grown outdoors in USDA Zones 5 and above. Make sure soil drains well – amend with sand or granite and well-rotted leaf mold or aged manure to provide humus. Check soil at least twice a week. If the top inch or two is dry, water the plant. Bamboo needs more water when newly planted or during shooting season when new culms appear.
Since over-watering is a common problem, you need to consider other possibilities before reaching for the hose. Shade-loving bamboos may develop curled leaves if exposed to direct sunlight. Too much water can also cause curled leaves. Check the newest leaves – if they are curled inward, it’s most likely to be a sign of under-watering.