Fertilization is too often neglected in the City as most people takes trees for granted believing trees will grow by themselves without access to essential nutrients. Proper fertilization will increase growth, reduce susceptibility to certain diseases and insect pests, and under certain circumstance, help reverse declining health.
Proper tree fertilization will include Nitrogen, Phosphorus and Potash that are required in large quantity, and also Magnesium, Sulfur, Boron, Copper, Iron, Manganese, Zinc and Molybdenum that are required in lower quantity but as essential as the three first one.
Ask Your Tree Doctor what would be the correct formula for your tree needs.