Process

• To graft a tree, a grower takes cuttings, called scions, from a certain tree with desirable properties. The grower then attaches or "grafts" these cuttings to a rootstock tree. This tree acts as the trunk, delivering nutrients and water to the scion. Because the scion and the rootstock are genetically related, the point at which the inner bark of the scion and the rootstock meets heals together. The two eventually grow to form a single tree.
  
  

Timing

• To graft most trees, growers select scions during the winter dormant season. The grower removes branches with several dormant growth buds from healthy trees, typically from the previous year's growth and stores them under refrigeration until spring. In the spring, just before bud break, the grower grafts scion to rootstock. When the season advances and trees begin to leaf out, the graft heals and the rootstock tree "nurses" the scion. This allows the scion a full growing season to become well-established.
  
  

Reasons

• Growers typically select scions from trees that have beneficial characteristics, such as attractive foliage or flowers, or high-quality or abundant fruiting. Rootstock trees are frequently chosen for their qualities as well, including increased disease resistance or hardiness in certain soil conditions. Combining these traits by grafting produces a tree that has the beneficial characteristics of both cultivars.
  
  

Techniques

• Several techniques exist for grafting trees, each designed to serve a specific purpose. For example, the whip graft joins scions and rootstock branches of similar size. The cleft graft is often used to connect small scions to larger side branches or the trunk of the rootstock and several scions may be set in the same graft. Another type of grafting, called budding, implants only a single bud from the scion tree into the bark of the rootstock tree. The bud eventually grows to form a branch, which is trained as the main leader of the tree.
  
  

Specialized Grafts

• Some grafts are not strictly intended to join scion to rootstock. The bridge graft is a good example. This graft acts as bandage for a tree with a damaged trunk. Small branches of the same tree are cut, then inserted across a section of bark that has been girdled. These branches grow into the bark, providing a path for water and nutrients to flow, saving the tree.
  
  

Multiple Grafts

• Another interesting use of grafting is the creation of a "fruit cocktail" tree, which has multiple grafts from several varieties of fruit. For instance, an apple grafted in this manner may bear red delicious, golden delicious, Winesap and Jonathan apples, all on the same tree. While it is possible to graft fruit trees of the same species, grafting different species, such as an apple tree to an orange tree will not work, as the plants are genetically incompatible.