graft

A graft is a section of stem, typically 3 to 6 inches long, cut from a fruiting tree and inserted into a cut or notch on the trunk or branch of a different tree, called the stock. The two pieces are held together with binding material and sealed with wax or grafting compound. Over weeks, the cambium layers of both pieces fuse, creating a vascular connection that allows the scion (graft) to draw water and nutrients from the stock's root system while the stock gains the fruiting characteristics of the scion.

Grafting exists because seedling trees often take 5 to 10 years to produce fruit, and seedlings from premium varieties rarely reproduce their parent's qualities genetically. A graft copies the parent tree exactly and fruits within 2 to 3 years. The practice is essential in commercial orchards: apple, pear, peach, and citrus growers rely on grafting to ensure varietal consistency and to match scions with rootstocks selected for disease resistance, hardiness, or dwarfing effect. A dwarf rootstock, for example, restricts the tree's final size while the scion determines fruit flavor and yield.

Common grafting methods

Whip grafting is used for small stock and scions of similar diameter: both are cut on a long slant and interlocked. Cleft grafting splits the stock vertically and wedges one or two scions into the cleft. Bark grafting lifts the stock's bark and slides the scion underneath. Budding, sometimes called bud grafting, inserts a single bud instead of a whole scion shoot; it is faster and uses less scion material, making it the standard in large-scale nurseries. Timing matters: most hardwood grafting occurs in late winter when scion wood is dormant; budding is done in summer when bark slips easily from the wood.

Graft failure occurs when the cambium layers do not align properly, when moisture enters the union and causes rot, or when stock and scion are incompatible. Some tree pairs simply will not unite; pears rarely graft successfully onto apples, for instance. Scion wood must be collected from disease-free trees and stored cool and moist. The union is vulnerable to frost crack and sunscald in the first winter, so many growers paint or wrap the graft site for protection.

The term graft derives from the Old French greffe, originally referring to a stylus or writing implement because of the pencil-like appearance of the scion stick. In trade usage, graft refers both to the scion itself and to the operation of grafting, and the resulting fused unit is sometimes called a grafted tree or described by its rootstock name, such as M.26 or MM.111 apples, which denote the Malling and Malling-Merton series rootstocks developed in the mid-20th century.