Commercial apple trees, such as crab apples, do not produce the same variety of seed as the fruit themselves. In order to ensure a new crab apple tree produces these delicious and tiny apples, a different form of propagation is required. Grafting is the process of combining a twig or branch of a crab apple tree with the branch or root of an established locally grown tree.
Select young twigs from a crab apple tree that are roughly 6-8 inches in length. Cut them from the tree and place the cut end into a bucket of water.
Prepare the stock branches by cutting them to a length of 12 to 18 inches in length. Cut a 2-inch-deep slice directly down the center of the branch for insertion of the scion.
Cut the end of the scion so that it forms a 2-inch wedge at the bottom.
Insert the wedge end of the scion into the cut on the stock branch.
Wrap the entire graft with rubber electrician's tape. The rubber tape will stretch and eventually fall off as the graft heals and grows.