If in doubt I recommend an all purpose slow release plant food such as Osmocote. If you have not had a soil test it is difficult to know what nutrient you soil is lacking but the plant will take only what it needs and Osmocote has all the macro and micro nutrients needed for your bamboo. Just follow the dosage on the package and you will not need to worry about fertilizer burn. Osmocote only needs to be applied once during the growing season. Keep growing, Marianne Binetti