We planted a very young bare root grafted weeping cherry tree three years ago. The tree has grown well and looks healthy.
I would expect a bare root grafted cherry tree that was planted three years ago to bloom this year. The excessive winter weather we had may have delayed the bloom. Since the tree is leafing out, the graft has taken. Make sure that there are no branches growing from below the graft. Cut them out. Fertilze with a balanced fertilizer like 5-10-5 now and in late July. Is it growing in the shade? The tree should get at least 6 hours of sun each day.