Cleft-grafting

Publication 457 - Revised by John W. Jett (1997)

Cleft-grafting, the most popular method of grafting apples and pears except in the nursery, is perhaps the oldest method of grafting because of the simple procedure. Cleft-grafting may be performed on main stems or limbs, providing they are one to two inches in diameter.

Cleft-grafting is relatively simple to do but there are certain steps that should be carefully followed to obtain the desired results.

  1. Select scions from well-developed terminal growth of the previous season, preferably those that made a growth of 12 inches or more. Gather the scions when they are dormant, and store them where they will remain dormant and not dry out (like in a plastic bag in the refrigerator) until time of grafting. (Actual grafting is best done in the spring when the bark of the understock begins to slip.)
  2. Choose a smooth section of understock to receive the scion. This area should have straight grain for at least six inches below the cutting point. This area should also be free of spurs, knots, and cankers. Remove the undesired section with a fine-tooth saw just above this point.
  3. Using a grafting blade (clefting tool) or a clean sharp blade, make a clean cut or cleft two to four inches deep. Cut the bark ahead of the split if it does not part evenly. If the graft is to be made on a branch growing on a horizontal plane to the ground, the cleft should also be made horizontally to the ground rather than vertically. Otherwise the bottom scion may grow upward into the upper scion.
  4. Remove the blade and insert wedge into the center of the cleft to hold it open for the insertion of the scion (Figure 1).
  5. Cut off a piece of scion wood containing three or four strong buds and, starting at the base of the lowest bug (Figure 2A), make two smooth, straight cuts to form a blunt wedge one to two inches long. The side containing the lowest bud should be slightly thicker than the other edge (Figure 2B). Note that the taper is not too great. (Generally two scions are used per graft.)
  6. Insert these scions into the cleft, one at each side as shown in Figure 3. The lowest bud on the outside of the scion should be placed just above the cleft, making contact between cambium layers of the stock and scion (Figure 4). It should be noted that the cambium layer is a very thin, colorless layer between the bark and the wood.
  7. Remove the wedge carefully (by moving it back and forth sideways) in order not to disturb the scions and permit the cleft to close solidly on them.
  8. Cover all cut surfaces with a nontoxic asphalt emulsion or with grafting wax -- preferably brush wax (Figure 5). Make certain that all spaces around the scions are filled with coating, eliminating all air pockets and preventing water from entering the graft.
  9. Check the scions periodically to determine the success of the graft. If both scions have "taken," one should be dwarfed after the first year to allow for better growth of the other (Figure 6A). The dwarfed scion may be completely removed as the cleft begins to seal completely. If one of the scions dies, that portion of the understock should be removed after the second year (Figure 6B). The cut should be coated with a tree wound compound.