How to Graft Mandarins

Select a hardy citrus species to use as your rootstock, such as Trifoliate orange. Confirm with a local horticultural expert, familiar with your climate, that your rootstock can thrive with your local soil, temperature and precipitation. Plant the rootstock in the ground and water it regularly. Wait a few weeks, until it has adapted to its new location, before grafting.

Cut a piece of a mandarin tree around a new bud that has just slightly hardened. Cut the piece to include a broad section of bark, so that 8 to 12 inches of wood are exposed. Center this patch of bark so that the new bud is centered. Wrap the piece of mandarin tree in moist paper towel and store it in a cool place.

Use a sharp knife to make a vertical cut into the trunk of your rootstock, about 6 inches above the ground. Make a second horizontal cut at the bottom of the vertical one to form an inverted "T" shape. Do not cut through any buds on the rootstock.

Insert the cut piece of the mandarin branch in underneath the flaps of the "T" cut. Wrap the grafted piece of mandarin tightly against the rootstock with budding tape. Wrap the tape around the grafted piece at least two or three times, wrapping at the bottom and top of the graft area.

Cut off any shoots growing from the rootstock, below the grafted piece, as they can overtake the grafted mandarin piece and keep it from developing. Force the new mandarin piece to grow by cutting two-thirds of the way through the rootstock about 1.5 inches above the bud, on the same side as the bud. Use string and a stake in the ground to pull the entire tree so it leans to one side, with the mandarin bud oriented upward.

Cut off the rootstock entirely when the mandarin piece has grown 3 to 4 inches. Make the cut about 1 inch above the mandarin piece. Remove the tape within 30 days once the bud appears green and healthy.