Is your maple in a container? If the tree is mature and growing well in the ground it does not need any additional fertilizer. If it is in a container or showing some signs of lack of nutrients (small or pale foliage, yellowing of leaves) then using 4 tablespoons of Osmocote around the base of the tree and working this into the top one to two inches of soil would be a good amount to use. The plants take up only the nutrients they need from slow release Osmocote so you don't need to be as careful about overdosing and causing fertilizer burn. Keep growing, Marianne Binetti