For avocados, grafting is used to join a high-quality, fruit-bearing stem, known as a scion, from one tree to the hardy, disease-resistant root stock of another. The two will eventually merge to form one plant and the resulting growth will produce fruit that is identical to the tree it was taken from. Whip grafting is a relatively easy way to graft to small root stock and is any effective method for grafting avocado trees.
Collect scions from the desired fruit-bearing tree in late winter before buds have opened. Wrap the scions in a damp paper towel, put them in a plastic bag and store them in the refrigerator until needed.
Graft in the spring when buds on trees that will act as root stock are just beginning to open.
Cut off a branch from the root stock tree no more than 1/4 inch in diameter with a sharp knife. Leave about a 1-foot stub. Cut on a wide angle that reveals as much inner bark as possible.
Split the branch by making a small cut on the side of the angle down into the center to form a small tongue. Do not split the branch too deeply.
Select a scion that is, ideally, the same diameter as the root stock branch. Remove all but the last bud from the scion.
Trim the cut tip of the scion at the same angle and split the same as the branch cut.
Insert the scion into the branch at the splits so the tongues wedge together. Align one edge of the inner bark of the scion to contact the inner bark of the root stock.
Bind the union tightly with grafting tape, then cover the tape entirely with grafting compound.
Continue to feed and water the root stock regularly to encourage growth.
Remove the tape as soon as the scion shows signs of growth.