Grafting is a method of propagating fruit trees without pollination. This allows fruit growers to take desirable fruit from one plant and graft it onto the roots of another, stronger plant, combining the best elements of both. Some fruit varieties do not create a seed that produces the same fruit, making grafting the only way to propagate the plant.
Whip grating is the most common method of fruit grafting. A scion, or branch from a desirable fruit tree, is grated onto the root stock that is more resistant to root rot and other diseases. Whip grafting is most successful when performed in January or February. Scion wood is cut when dormant and placed into refrigeration until spring. The scion wood should be from the previous season's growth. The scion wood is brought out of refrigeration in the spring and cut along the bottom so that a 1/4-inch tongue is present, according to the Alabama Cooperative Extension. A similar cut is made along the root stock and the two pieces are placed together and bound with grafting tape. The tape is removed after several weeks, once the graft is healed.
Cleft grafting is used to grow new varieties on top-working trees. Scion wood is collected and removed from refrigeration in the spring, before new growth occurs. Branches are cut off of the stock tree to prepare it for the scion. A split is made in the area of the removed branch using a wedge. The cut is held open as the scion wood, cut into three bud pieces, is entered into the split. The scion wood is covered with grafting wax, and the scion wood covered with a paper bag and left to heal.
Like cleft grafting, bark grafting requires a branch to be cut off of the stock tree. The scion wood, cut into three bud pieces is held against the stock. The scion wood is slipped under a section of loosened bark, then tied into place using a soft piece of string or wire brads. The area is covered in melted grafting wax, and a paper sack is put over the scion wood for three to four weeks until it begins to bloom.
To ensure success, it is important to keep the scion covered as it attaches itself to the stock. Suckers, small offshoots from the scion, require removal as soon as they appear. When a scion makes long, slender growth, it requires cutting back to create lateral branching.
Grafting is difficult and may not take the first time, states the University of Minnesota Extension. When the scion is not healthy when being grafted, or the scion and stock are not compatible, the graft may fail. Scion that is placed upside down, not covered properly, or is attacked by birds or bad weather will have little chance of success.