The whip-and-tongue graft is used to make a secure graft with a lot of surface area contact between the scion and rootstock. It is used to connect thin pieces of stock and scion, usually roughly pencil-thick, but it probably requires the highest fine skill of all grafts. If this proves too difficult or you have not grafted before, start with the splice graft instead.
When to Use a Whip-and-Tongue Graft
Instead of the simpler splice graft, which has two faces, this graft creates a “whip” and a “tongue” that each have two faces on both scion and rootstock—a total of eight faces. That’s four times as much contact, which means a greater chance for the graft union healing to occur.
The downside is the tongue cut is a technically difficult and potentially dangerous cut, during which the sharp knife can easily slip and slice a finger if done wrong. Without great practice, this method is slow at best, and painful at worst.
It's not common to use this type of graft in a home garden unless you were playing with novelty grafting to add many different scions to a fruit or ornamental flowering tree. In these cases, where you might want to put different kinds of pears on a pear tree, or different cherries on a cherry tree, the wood you work on might be small enough. Another and possibly better option would be to make fewer grafts and work instead on a thick branch with a cleft or side-stub graft.
Equipment / Tools
- Grafting knife
- Rootstock and scion of the same size, a 1/4 inch up to a 1/2 inch. Scion has at least three healthy buds
- String and plastic tape or sealing wax
Sharpen Your Knife
It must be as sharp as possible for this graft. If it is dull you will attempt to make the cut by increasing the force you apply, which will increase your risk of slipping. A dull knife is more likely to turn as it passes through the wood, making a wavy cut.
Make the First Cut
In one stroke make a long, smooth cut angling across an internode at the top of the rootstock to create an oval face about one inch long, or longer if your wood is thicker. When doing this, hold the wood tightly in one hand and your knife tucked tight in four fingers of your cutting hand, with that hand’s thumb stuck straight out. The cut is a single, straight pulling motion, pulling sideways across your chest and away from your hand holding the wood. None of your fingers move from the position during the cut, thus keeping your thumb in front of and out of the way of the knife.
Cut the Scion
Make a cut of the same length and angle across the base of the scion.
Make Sure the Cuts Match
Place these cuts against each other now and see that they line up well, having the same angle and a straight, not wavy, face. When placed against each other, there should not be air gaps or exposed inner wood. If there is a problem, now is the time to try to correct it with recutting.
Make the Tongues
This is the difficult and dangerous cut. Starting about 1/3 of the way down from the tip of your wood, you must cut into the face. Your cut should be straight, about half the length of the first cut, and parallel to the first cut. Make the same cut in both scion and rootstock. When completed, the two pieces can be fit together in an interlocking manner.
Create the Graft
Slide the scion and stock together to interlock. The tongues will fit snugly together and the wood’s natural tension should hold the graft tightly, with minimal or no air space between the pieces of wood. If the thicknesses are slightly different do not center the scion. Rather, offset it to make sure one of the two sides line up smoothly.
Seal It Up
Bind and seal the graft by wrapping it tightly top-to-bottom twine covered with plastic tape or sealing wax.
Follow up with general aftercare, such as humidity control, until the union fully takes.