Bonsai Fertilizer – Spring Development Mix 4oz PackN-P-K9-4-5 This is a three month slow release mix with an organic component. It is best for trees needing robust development and will encourage vigorous growth. It comes will a full micro nutrient package and will help your trees to thrive and flower like wild. Evenly spread the fertilizer around the pot avoiding piling any fertilizer on the trunk or nebari (roots neat the base) which can burn the tree. Amount to be used varies according to tree and pot size. An average 8″ pot with a 12″ tall tree may take as much as 1/2oz.