Many home gardeners consider grafting to be difficult. However, most gardeners can successfully graft fruit trees with a little practice. Grafting can be a very important tool for the home gardener. For example, if the identity of an old, declining apple tree is unknown, grafting becomes the only means to perpetuate the tree. (Fruit trees don't come true from seed.)
Grafting is the joining together of two plant parts (scion and stock) in such a way that they unite and become one plant. When grafting fruit trees, the scion is a portion of a twig taken from the desired tree or variety. It comprises the upper portion of the graft and develops into the fruit producing branches of the new tree. The stock (rootstock) is the lower portion of the graft. The stock becomes the root system of the grafted plant.
Whip or tongue grafting is an easy method for propagating apple trees in the home garden. This type of graft is made when the stock and scion are dormant. The stock and scion should be the same diameter, preferably between 1/4 and 1/2 inch. Scion material should be collected when fully dormant (February or early March) from the previous year's growth. If possible, collect the scion wood when the temperature is above freezing. Place the scion wood in a plastic bag containing moist sphagnum moss or sawdust. Store the scions in the refrigerator until it's time for grafting. Rootstock material can be obtained from selected mail-order nurseries. Both standard and dwarfing rootstocks are available. (The names and addresses of several mail-order nurseries that sell apple and other fruit rootstocks are listed at the end of this article.) If dwarf apple trees are desired, suggested apple rootstocks for Iowa are Malling 7A, Malling 9 (needs to be staked), and Malling 27 (very compact, also needs staking). The three rootstocks are commonly abbreviated M 7A, M 9, and M 27 respectively. Virus-free material is listed as EMLA 7, EMLA 9, and EMLA 27. Recently released dwarfing rootstocks include Geneva 11, Geneva 16, and Geneva 30.
The first step in whip or tongue grafting is to make a smooth diagonal cut through the stock 1 to 2 inches long. Use a sharp knife to ensure smooth, even cuts. Starting about 1/3 of the way down from the pointed end, make a second downward cut into the stock to form a tongue. The second cut should be 1/2 to 1 inch long, slanted toward the base of the first cut. Using the middle portion of the scion wood, prepare the scion in the same manner as the stock. The stock and scion are then slipped together, the tongues interlocking. Next, wrap the stock and scion firmly together with grafting tape or 1/2 inch wide masking tape. Cut the scion off about 3 to 4 inches above the graft. There should be 2 or 3 buds on the remaining portion of the scion wood. Finally, cover the graft union area and the cut end of the scion with a grafting or pruning compound.
If whip or tongue grafting is done in early March when the ground is still frozen, place the grafted trees in a plastic bag containing moist sphagnum moss and leave them at room temperature for 7 to 10 days. Then place them in the refrigerator until the trees can be planted outdoors. Trees grafted after the soil has become workable can be planted outdoors immediately. Home gardeners may want to grow the small grafted trees in the garden for 1 or 2 years before transplanting them to their permanent site.
Plant Propagation: Principles and Practices
Hudson T. Hartmann, Dale E. Kester, Fred T. Davies, Jr. and Robert L. Geneve
Sources of Rootstock
391 Butts Road
Morton, WA 98356
Phone: (360) 496-6400
P. O. Box 157
North Lima, Ohio 44452
Southmeadow Fruit Gardens
P. O. Box 211
Baroda, Michigan 49101
This article originally appeared in the 2/13/2004 issue.