In whip grafting and cleft grafting, a twig or limb from one tree is grafted onto another. Those grafting methods are usually done in the spring to apple or pear trees. Cherry trees and other stone fruits, including apricots, peaches and plums, are not ordinarily whip or cleft grafted. They are grafted in the late summer employing “T budding” or “chip budding” techniques that attach a single bud to the rootstock, not a twig or section of limb.
Grafting is the art of taking a scion from one tree and attaching it another tree, the rootstock; a scion is a single bud attached to a small amount of tissue or a twig with one or two buds. Both the scion and the rootstock contain cambium, a slimy layer of tissue two cells deep between the bark and the wood. The cambium heals wounds; in grafting, the cambium of the scion and the rootstock fuses together.
After cherry trees have grown their leaves, their bark will slip easily on the wood when it is cut. This slippage is caused by the layer of cambium; on cherry trees it usually occurs from mid-July to mid-August.
The buds most favorable for grafting are slightly brownish mature buds growing from strong shoots of the current season's growth. The leaf is broken off just below the selected bud. The petiole is left intact; petioles are the slender stems by which leaves are attached to the twig. A cut is made just under the petiole and the selected bud. The cut should only be deep enough to take a sliver of wood along with the bud and bark. This is the bud stick or scion. Bud sticks should be wrapped in moist moss, paper or burlap so they will not dry out.
A cut in the form of a T is made in a smooth, open branch of the rootstock; this should be two- to three-year-old growth that is between ¾ and 1 ¼ inch in diameter. Flaps of bark are peeled back from where the stem of the T meets the top.
Grafting the Bud
The bud stick is inserted under the cut flaps and wrapped with grafting tape. The rootstock is cut off 6 inches above the graft. The petiole will fall off the bud in 10 days; the bud will remain dormant until it begins growing the following spring.
In chip budding, the scion and the rootstock are close to the same in diameter. A wedge-shaped piece of wood, or chip, is removed from the current season's growth of the rootstock. A wedge of the same size containing a bud in the middle is cut to fit the space left in the root stock. The wedge with the bud is inserted into the rootstock and wrapped with grafting tape.