Root grafting is a method of producing a new tree from a seedling rootstock. Whole roots or pieces of roots that are 3 to 4 inches in length can be attached to a scion, which is a young shoot or twig from a tree, that is as large as or smaller than the root. Root grafting is a common practice in producing healthy fruit trees that produce similar fruit, as healthy roots from a good tree can be used to create clone plants that behave in the same manner. Grafting stock fruit tree roots can be difficult and may require a few attempts before the grafting takes.
Cut a twig from the branch of a healthy, disease-free fruit tree that is 6 inches long and pencil thin. Cut perpendicular at a budding point on the branch, called a node, and wrap the twig in a wet paper towel and put in the refrigerator until ready to graft.
Select a rootstock that is at least 4 inches long and prepare the scion by cutting 1 1/2 inches from the bottom of it at a diagonal angle.
Make another cut at the bottom of the scion so that it is split into a forked tongue. Make another cut on the rootstock that matches this cut so that they fit together like a puzzle piece.
Attach the two pieces using grafting tape, making sure to wrap it well enough that it will not move.
Put the rootstock into wet sawdust until the graft takes, which should be within a few weeks. Keep the sawdust in a cool place to avoid stressing the graft.