Well I don't have or ever have had one, but there is one across the street from me, it is on the easement between sidewalk and street, been there for many years, blooming now. I don't think anyone has ever done a thing to it, but irrigation. It is sandy soil here and the tree is in full sun with nothing but grass around it. Is your tree getting enough sun? Most of them around here are yellow and they're in full sun.