I believe almost any citrus will grow on another citrus rootstock; maybe you are grafting it at a time when the rootstock is not actively growing, so it does not have sufficient sap to "heal" the graft. I would try budding instead; it is easier to learn and usually more successful; you could put 3 or 4 buds on a pencil thick root, varying in height and location around the trunk; with that you will get a more balanced and faster developing tree. I put my mandarins on Macrophylla because it grows so fast and produces lotsa fruit.

I'm not aware of any incompatibilities between any of the mandarins and rough lemon. On the other hand, if your scion wood happens to be infected with citrus tristeza virus, you may have problems on macrophylla or sour orange roots (rough lemon is tolerant). If not infected, any of the three should be fine. I, too, would recommend T-budding as easier and more successful, on citrus, than is cleft grafting, although I always say to use whatever method works for you, and if you've had good success with other varieties using clefts, there's no reason your mandarins shouldn't work as well.
Malcolm

Malcolm M. Manners, Ph.D.
John and Ruth Tyndall Professor of Citrus Science
Florida Southern College
Lakeland

Thanks for the suggestions. I'll try grafting the mandarin again. I'm relatively new to grafting.

My cleft grafts have been successful approximately 80% of the time (approx 100 grafts), but when I tried T-bud grafting about half dried out and died (sample size approximately 12). I may be cutting too deep, doing it at the wrong time, or doing something else wrong. The Agriculture Department here in Fiji also does cleft grafting on citrus, and I'll ask them why they don't bud-graft on my next visit with them.

The only problem with my cleft grafts is that when one fails I have to wait a couple of months before I can rework it.

Thanks,
John

Last year my expert nurseryman budded 4,125 Meyers for me and did not lose a single one!!! But he is a magician; when I try it, I am lucky to get 60%. For budding, first you want to be sure your rootstock is actively growing; then be sure your tools are sharp and sterilized; then, leave the growth and leaves above the bud until the bud starts to grow; then cut it off. Last be sure you use a good grafting tape and wrap the bud union tightly above and below the bud; if it is rainy time, paint the whole thing with white latex paint, the cheapest one, diluted 1 to 1 with water. Last, don't leave the tape on too long; for Meyers it only takes about 17 days for the bud to begin growth in warm climate. The big advantage for amateurs, like me, is I can put several buds on the rootstock; so even if one fails I still have a tree.