You don't mention whether you are growing an ornamental flowering cherry tree or one grown for edible fruit, so I cannot provide a specific answer. In general, how you fertilize depends on what nutrients are already available in your soil, and the best way to find that out is by having a soil lab test your soil. You can get a soil sample collection kit from the county office of the Cooperative Extension Service or in some cases from locally owned garden centers. The collection kit includes directions on how to collect the sample and where to send nit for testing.
You can encourage growth in young cherry trees by applying a fertilizer that contains nitrogen in spring. Follow label recommendations for amou ntIn many cases, if the trees mature enough to bear fruit, you do not need to fertilize. In fact, overfertilizing with nitrogen can delay or even prevent fruit production by promoting just leafy growth.