In most plants, yellow leaves indicate that the plant is sick and needs help to survive; however, many bamboo plants display yellow leaves as a routine part of their life cycle. Gardeners who have planted a new bamboo privacy screen or those who have bamboo plants must be able to determine when yellow leaves are normal and when they indicate the presence of a plant pest.
The American Bamboo Society and Bamboo Garden note that bamboo plants develop yellow leaves in the springtime naturally. This is part of the life cycle of the plant and should not be cause for great concern. Many leaves yellow then wither and drop from the bamboo. At the same time, developing leaves should appear that are green and look healthy. If you notice yellow leaves in the spring, it is probably seasonal.
Bamboo mites cause thin yellow tracks in the center of bamboo leaves. These are vertical and average 1/8 to 1/4-inch in width. Gardeners may be able to see tiny bugs within the yellow tracks. Only the center track becomes yellow; the rest of the leaf is healthy-looking and green.
Spider mites also infest bamboo and leave yellow track marks; however, they cause yellowing throughout the leaf and not only in a specific area. Leaves infected with spider mites may display browning at the tip or curling inward in addition to growing yellow from the damage.
Scale insects also cause bamboo leaves to turn yellow, but more on the margins of the leaves than in the center. Bamboo stalks may turn dark brown from the scale damage. These pests are more common in Asia than in North America, notes the American Bamboo Society, but they do occur in North America.
The American Bamboo society notes that bamboo plants can tolerate bamboo or spider mites much like a dog tolerates fleas. Bamboo plants will not die from mite infestations, but they will continue to bear yellowed leaves. Serious scale infestations can weaken the plant and eventually kill it or render it commercially worthless.
Gardeners can spray infected plants with insecticidal soap weekly to get the mite problem under control. Alternative treatments include miticides and horticultural oil.