Grafting is a popular mode of vegetative propagation in apples. In this process, a cut twig of a desirable cultivar is introduced into another compatible plant.
Growing apples from seeds usually end up producing apples of different taste. Also, the seeds are not viable in some cases, or they take long time to germinate and develop into a mature plant. Thus, grafting apple trees and other fruit trees becomes an easy option for propagating them, since seeds don't always produce exact copies of their parents.
In layman's language, grafting is defined as the method of uniting parts of two plants (a rootstock and scion) to grow as one plant. Whichever technique you adopt, grafting requires a healthy rootstock and a scion. A neat cut is made into the stock, which is then followed by positioning of scion into the incision on the stock. These basic steps may vary slightly, depending on the method you are following, but the premise remains the same.
Scion and Rootstock
The scion is taken from a desirable apple tree. It is the sample which has the variety that you actually want to propagate and harvest. Stringent care should be taken while choosing the mother plant for the scion. On the other hand, rootstock refers to the lower portion that houses the roots and supports the upper stem (scion). Although it is not involved in bearing fruits, selecting a healthy stock is of utmost importance in grafting. In short, both scion and stock should be free of harmful viruses, bacteria, and destructive diseases.
This technique is excellent for grafting old apple trees. A twig (or main trunk) about the diameter of 1-2 inch is selected for use as a rootstock. Make sure that the grafts are made at a height of 4-6 feet from the ground level. After deciding the spot for grafting, cut off the stock completely with an appropriate garden tool. Make a cleft with a grafting chisel or a sharp knife, and split it open with the help of a screw driver. The depth of the cleft should be sufficient to fit the scion perfectly.
Prepare two scions, each with 2-3 buds. The bottom of the scions should be trimmed into a blunt wedge shape. To each side of the cleft, gently introduce a scion in a slightly tilted position, making sure that the inside of the stem of the rootstock is in direct connection with that of the scions. Hold the cleft around the scions and fill the whole length of the cleft with a grafting compound. In order to avoid breakage of scions, you can support them with stakes.
In this method, a single bud serves as a scion instead of the whole stem. It should be preferably done in the summer season, when plenty of mature buds (slightly brown) are developed in the mother plant. Cut a branch having healthy buds, and discard the leaves. You can wrap it with moist sawdust to prevent drying. Make a T-shaped cut in the bark about 15 inches away from the main trunk. Using a knife blade, loosen the bark and keep it ready.
Detach a bud with thin wood. Lift the bark gently in the rootstock, and place the bud inside. You can use adhesive tape or rubber strips to tie the bud and stock together. Finish off your grafting by securing the bud to the stock, without actually covering the bud portion. As the bud starts growing in the active season, trim off the stock just above the bud level with the help of a sharp cutting tool.
No doubt, grafting fruit trees may sound challenging for novice gardeners. But, once you get to know the quite simple procedure, and with practice, it becomes surprisingly easy. Once you are familiar with the basic steps, you can experiment with grafting two or more scions of varied cultivars to the same rootstock.