M. Elena Garcia, Renae E. Moran, Lorraine P. Berkett, Terence L. Bradshaw, Sarah Kingsley-Richards, Heather M. Darby, Robert L. Parsons, John P. Hayden, and Morgan L. Cromwell
Top-grafting is the process of changing a tree from one cultivar to another by means of grafting. It is done in the spring, shortly before new growth starts. The exact time depends upon the method to be used. For example, the cleft graft is performed before the bark is slipping; the bark graft is done when the bark is slipping, but before the buds of the stock begin to grow. There are a number of advantages to top-grafting an established orchard compared to pulling out the trees and planting a new orchard at the same site with young, nursery trees. These include a shorter time for trees to come into bearing, avoidance of replant problems, and the advantage of an already established root system. However, the trees that are selected to be top-grafted need to be ‘healthy’ and in a site that has no problems such as poor drainage. Also, please remember that any cultivar which is patented requires propagation agreements.
The following are the steps that were taken to top-graft an 18 year-old apple orchard (using a cleft graft) at the University of Vermont Horticultural Research Center, South Burlington, VT. This orchard is part of a USDA Integrated Organic Program project and will be managed using organically-accepted methods. Please note that there are other options or other techniques that can be used to top-graft an orchard. This publication is solely intended to be a pictorial presentation of some of the techniques available to you.
Original 18 year-old apple orchard before top-grafting
Seal tips of scions with balls of wax.