Plant grafting is the joining of two plant segments, called the scion and rootstock, from two different plants in the same species. The two segments will then grow together and form a single plant. The scion consists of a shoot from which branches and stems will grow, and the rootstock functions as the root system for the new plant. Grafting is performed to alter plant size, enable propagation, increase a plant's resistance to disease, or to repair damaged areas of an otherwise healthy plant.
Cleft grafting is used primarily on fruiting and flowering trees, such as apple trees, cherry trees and peach trees, to change the variety of the plant. According to North Carolina State University, cleft grafting is best done on main stems or scaffold branches during the winter and early spring and involves making a cut, or cleft, through the center of the stock and inserting a scion into each end of this cleft.
Bark grafting involves making vertical slits through the bark of a plant's rootstock, and then inserting multiple scions around the rootstock. Bark grafting is preferred over cleft grafting when rootstock is at least 4 inches in diameter. It is performed in the early spring when tree bark is easily removed from the wood.
This grafting method is an ideal choice for propagating conifers that are slow growing. Veneer grafting involves removing bark from one side of the scion and from a portion of the rootstock, and then placing the exposed cambiums together.
Splice grafting is a simple technique used mainly on plants with a stem diameter less than 1/2 inch. Splice grafting involves joining a scion onto an intact root piece or only a rootstock stem.
Whip and Tongue Grafting
This type of grafting technique is commonly used on woody ornamentals or nursery crops. It is very similar to splice grafting, according to North Carolina State University.
Saddle grafting is used to propagate evergreen rhododendron and is a quick and easy grafting technique. Saddle grafting works well on both potted and field-grown stock, provided the stock is dormant and less than 1 inch in diameter. In saddle grafting, an inverted V shape is cut from the top of the rootstock. A V is then cut into the base of the scion, and the two pieces are joined together.
In cases of plant disease or damage, bridge grafting can effectively create a bridge over the area to provide support and ensure nutrients and water are able to reach all areas of the plant. This type of grafting is performed during early spring before active plant growth begins.
Similar to bridge grafting, inarch grafting is used to bypass a damaged area of stem. The difference between the two methods is that inarch grafting uses an existing shoot or sucker from the same plant that is growing below the injury and extends the growth to a point above the injury. Water and nutrients can then travel from below the damaged area to the top of the plant.
Bud grafting involves using a bud instead of a stem for a scion. Ohio State University states that bud grafting is easier and faster than other grafting methods, and is ideal for propagating roses and ornamental shrubs.