Is tree fertilization right for my trees? Soon it will be spring and time to begin our spring fertilization program. You may be wondering if tree fertilization is right for your trees. The answer to that question can be complicated, but I am here to try and simplify things. Trees in the urban landscape face a number of unique challenges that can limit their growth and potential; they also face an increased mortality rate before reaching maturity. What challenges do urban trees face and how can fertilization benefit?