Grafting is one of the methods of propagating nut trees. This asexual method involves cutting a twig from a mature nut tree and joining it to the bark of a younger but similar nut tree. The intersecting point is called “union” and is covered with grafting tape or wax to ensure a secure bond. If carried out properly, the grafted twig binds itself to the tree and grows with it. This horticultural practice is done to increase nut production and improve quality. Walnut trees are among the most commonly grafted nut trees.
Cut a twig from a nut tree with a scalpel in mid-March when the tree is dormant. Make sure the twig (also called scion) is 5 to 6 inches long and has three to four buds from last season.
Dip the ends of the scion wood in paraffin wax or melted candle. Wrap it in a moist paper towel. Place the twig in a paper bag, seal and store it in the refrigerator until spring.
Make a 2-inch-long vertical cut in a branch of a mature nut tree. Make sure it is double the thickness of the scion wood. Work slowly so you cut the bark, not the nutrient-dense tissue underneath (sapwood). Make a horizontal cut over the vertical one to form a “T.”
Prepare the scion wood. Cut 2-½ inches of wood from the lower end of the scion. Turn it over and shave away the bark behind the previous cut. Make a chisel cut on the tip of the scion.
Lift the bark carefully with the tip of a sharp knife where both the cuts intersect. Make sure you do not cut the bark when doing this.
Insert the flat, cut surface of the scion wood under the lifted bark. Slide it vertically between the lifted bark and sapwood. Hammer two ½-inch long nails that penetrate the bark, grafted scion wood and sapwood to hold the scion in place.
Cover the entire grafted area with grafting wax, which secures the bind so the scion attaches itself to the tree and grows a limb.