Q. How can I save my bamboo plant that is yellowing?
If only a few of the leaves on your bamboo plant are yellowing then this is not a problem as it is a natural phenomenon for evergreen plants. If most of the leaves or stems are yellowing then this is a sign that that the growth conditions under which the plant is growing are not ideal.
Unfortunately, it is difficult to pinpoint a particular cause. Bamboos need slightly acidic, rich soil so an annual feed of organic compost will help. Otherwise, check for over-watering or under-watering. Stressful conditions, such as wind or too much or too little sun (depending on the species) can also be a problem. Also, check your plants for insect pests. Finally, pruning the plant may help by producing fresh growth.
If you are growing the bamboo indoors, then providing sufficient humidity may be difficult. Try growing the plant on a humidity tray. Keep the soil slightly dry but do let it get completely dry Also, feed with a weak solution of high nitrogen fertilizer throughout the growing season.
Please note that these hints do not apply to "Lucky Bamboo" (a popular indoor plant), which is not a true bamboo.
Courtesy of NYBG Plant Information