An approach graft is an easy graft to make in the right specialty situations. It happens naturally in the wild when two branches rub against each other and eventually seal together. In the garden or greenhouse, you use it to join one whole living plant to another.
You can only use an approach when the plants are growing close together or can be brought closer together. That’s a limitation. An advantage, though, is that both the eventual scion and rootstock are nursed by their own roots while the graft heals, so graft failure is extremely rare.
Just to observe your first easy graft union, to play around with grafting, or to attempt some inventive grafting art, approach grafting can be the way to go, though it has other more specific uses.
Why You Might Use an Approach Graft
With plant growing in pots indoors, which can be easily moved around, you can use approach grafting easily because you can rearrange plants to be close together as your needs dictate. It’s easy to join a scion from one neighbor onto the roots of another.
Outdoors, there are few “practical” uses for approach grafting. Plants rooted into the ground are obviously not meant to be moved, but there are times you might plan your plantings with later approach grafts in mind:
- To make a living fence. When making a living fence, a row of same-species plants is planted close enough that they will grow into each other along a line. In an artful form of living fence, the major branches are trained to cross each other and approach grafted at the crossing sites. These grafts become extremely strong over time.
- In grafting tropical fruit trees, and other hard to graft species. Since they work well on non-dormant plants, approach grafting is a common method for many tropical fruit trees.
- If you have to graft during the growing season. If you must, for whatever reason, work on a plant when it is not dormant, your options for grafts are very limited. Splice, side-veneer, cleft, and other similarly popular grafts all require dormant wood. Approach may be the only suitable way to graft your plant in-season.
- To produce living sculpture, horticultural art, such as the masterpieces of Axel Erlandson.
What You Will Need
- Actively growing plant material. This cannot be done during dormancy.
- Two complete plants which can be brought into contact with each other at the desired site.
- A grafting knife.
- A tight binding such as raffia twine or poly grafting tape.
- Plastic tape or sealing wax, or similar moisture control.
- For an inlay graft: long nails and a hammer.
How to Make an Approach Graft: Three Methods
- Spliced Approach Graft: On branch diameters of the same size, this is the simplest graft to make. Slice into the bark and wood of the rootstock branch with your knife, making a smooth wound a couple inches long. Make a matching cut on the scion. Bring these wounds into contact and bind them very tightly together, then cover the whole area with wax.
- Tongued Approach Graft: This is much more complex than the spliced, and resembles a whip-and-tongue. Make the cuts for a spliced approach graft as described above. Then, just as you would make the tongue of a whip and tongue, slice upwards and into the wound of the scion, and downwards and into the wound on the rootstock. You know have two interlocking, springy tongues that can be joined tightly, bound, and waxed.
- Inlay Approach, for different sized branches: When you join a much smaller plant to a branch with comparatively thick bark, the inlay approach is right for you. In this graft, you cut a 3 inch or so rectangle of bark and the top layer of wood out of the rootstock. The rectangle is the exact width of the scion. You then make a matching wound on the thinner scion, as you do in spliced approach. Match the wound faces together and drive nails through the scion into the rootstock to tightly hold them, then cover it all with wax.
For all grafts, remember to practice good aftercare to help them heal, including the use of a shadecloth if your plant is outdoors and will receive direct sun.
Hartmann, Hudson T., and Dale E. Kester. Plant Propagation Principles and Practices, 7 ed. 2002.