Grafting is a process where the rootstock of a plant is joined with a scion cutting of the plant to form a new branch. It is a process that requires a certiain amount of precision, but is very valuable for combining different types of trees and for other purposes. On this site I will be describing the process for a simple cleft graft of a dogwood tree, scientifically known as Cornus florida.
Below is shown a piture taken off of Google images of a flowering dogwood tree.
Time for Grafting
The best time to graft any type of deciduous tree is when both the rootstock and the scion are dormant. This is generally the winter or very early spring.
Selecting and Cutting Scions
The most important part of cutting your scion material is to use sterile tools. If you aren't careful about this, you can spread diseases easily. Isopropyl alcohol is a good sanitizer, or you can use a ten percent bleach solution. You will want to only cut as many scions as you plan to use that same day, however, they can be stored for a short time in an iced container of some kind if need be. You will need two scions per each rootstock for a cleft graft. Each scion needs three to four buds. Make sure that the plant you are cutting scions from is insect, disease, and winter damage free. They should be about pencil length and pencil width. That is about 1/4 of an inch in diameter and 6 to 8 inches long. Store them in a moistened bag until you are ready to do the grafting.
Preparing the Rootstock and the Scions
To prepare the scions, you must cut about 1 and 1/2 to 2 inches off both sides of the scion at the basal end at an angle to create a wedge shape. To ready the rootstock, first cut the rootstock perpindicular to the stem to create a horizontal surface. Now take a wedge cleft tool and a hammer to split the rootstock in half down about two to three inches. Insert the pick end of the tool into the split to hold it open for the graft.
Now for the actual grafting. Take the two scions and insert them into the cleft you created in the rootstock. The wider end of each scion should be facing the outside of the cleft. Make sure that the cambium layer of the scions ligns up with the cambium layer of the rootstock. This is absolutely crucial; if this isn't done right your scions won't take. Now remove the clefting tool from the rootstock, and the cleft will close and hold the scions in place. Finally, use grafting wax or grafting paint to seal any surfaces that you cut to prevent drying and to keep out excess water. Grafting paint may be a better choice because it doesn't need to be heated. If grafting wax gets heated too much you can damage the plant, and if it isn't heated enough it won't cover the cut areas properly. You can also add nurserymans tape to hold the scions if you want to, but it isn't necessary. Generally one scion will grow faster than the other. After some time you may prune off the slower growing scion to give the faster one more room to grow.
Shown below is a depiction of cleft grafting taken off of Yahoo! images.
3. The Grafter's Handbook by R.J. Garner, accessed as an E-book online at Google books