Citrus trees are grafted onto root stock like most fruit trees. We visited some friends with a Buddha's Hands Citron and I have a cutting. I have never propagated citrus but will try a tip cutting and a woody stem cutting. I am reading that most citrus are bud grafts. I would try that too but this citron is a zone warmer then mine. I guess I am not optimistic about this working but have been surprised many times when they take. When I hit upon the right method for a cutting they grow like weeds. Good luck.