I have an idea I am going to try on some of my citrus trees. I think it was in a post by Stan where he mentioned that high grafting will provide additional cold resistance, but buddinman pointed out that high grafts are difficult to bank which is the only way really save the tree in a hard freeze. However, JoeReal said he does a lot of his grafting on rootstock sprouts below the graft.

So, I am planning to let some of the rootstock sprouts on my satsumas get big enough to do some high grafts of other varieties. I will leave the original graft that is only a few inches above the soil in case of a hard freeze so that I will be able to bank it.

The only problem I can forsee is the difficulty of keeping the high graft rootstock from continuously sprouting.