Grafting involves physically joining parts of two different plants so they grow together and function as a single organism. This technique is the primary method used to propagate specific persimmon cultivars, ensuring the new tree produces fruit identical to the desired parent variety. The process works by fusing a small cutting, known as the scion, onto an established root system called the rootstock. This allows growers to combine the desirable fruiting characteristics of one tree with the strong, hardy root system of another.
Understanding Persimmon Grafting Needs
Persimmon seeds rarely produce a tree that yields the same high-quality fruit as the parent, a phenomenon known as not growing true from seed. Grafting overcomes this genetic variability by cloning the desired cultivar, guaranteeing the fruit’s specific size, flavor, and texture. The procedure unites the fruit-bearing scion wood with a rootstock selected for its ability to anchor the tree, thrive in local soil conditions, and resist disease.
The most common rootstock choice is seedlings of the American persimmon, Diospyros virginiana, because it offers superior cold hardiness and adaptability to various soil types. This rootstock is broadly compatible with both American persimmon cultivars and most Asian persimmon varieties, Diospyros kaki. While compatibility is high, some pairings, particularly with certain Asian cultivars, can occasionally suffer from delayed graft failure. A successful union depends on the two plant parts creating a seamless connection.
Essential Preparations: Timing, Tools, and Materials
Successful persimmon grafting relies on precise timing, typically occurring when the rootstock is just beginning its active growth cycle in late spring or early summer. While the rootstock should be starting to push leaves, the scion wood must remain completely dormant, having been collected earlier (usually between January and early March). This dormant wood, ideally one-year-old growth with a pencil-like thickness, must be stored carefully in a refrigerator between 32 and 40 degrees Fahrenheit to prevent freezing or premature bud break.
The viability of the scion wood is maintained by preventing moisture loss, often by wrapping it tightly in plastic or slightly damp moss and sealing it in a plastic bag. Maintaining a sharp edge on all cutting tools is necessary, as clean, flat cuts maximize contact between the cambium layers of the rootstock and scion. Necessary tools include a specialized grafting knife, bypass hand pruners, flexible grafting tape, and grafting sealant or wax. The grafting knife is designed with a flat bevel on one side to facilitate the long, smooth cuts required for the whip-and-tongue method.
Step-by-Step Guide to the Whip-and-Tongue Graft
The whip-and-tongue technique is effective for joining young persimmon wood where the scion and rootstock diameters are closely matched, ideally around a quarter to a half-inch thick. The first step involves preparing both pieces by ensuring the scion and the rootstock at the grafting point are of similar girth. The initial cut is a single, smooth, diagonal slice made on both the rootstock and the scion, approximately one to two inches long, executed with a single, steady pull of the grafting knife.
The precision of this diagonal surface determines the success of the graft, as it maximizes the area for cambium contact and subsequent healing. Once the main slanting cuts are made, a small, downward-pointing notch, or “tongue,” is cut into the center of the diagonal surface of both pieces. This secondary cut should be about halfway down the initial diagonal surface and is made by gently pushing the knife into the wood parallel to the main axis of the stem.
The rootstock and scion are then carefully interlocked, fitting the tongue of one into the notch of the other, which creates a strong physical connection resembling a zig-zag or “Z” shape. This interlocking holds the pieces securely in place while the union begins to heal. The step is ensuring the cambium layers (the thin tissue just beneath the bark) align perfectly on at least one side of the union to allow for the formation of callus tissue.
After alignment, the entire union must be tightly wrapped with grafting tape, such as Parafilm, starting below the cut and extending above it to prevent air and moisture from entering the wound. Finally, the tip of the scion wood and any other exposed cuts are coated with a grafting sealant or wax to completely seal the wood against water loss and pathogens.
Leaving two or three viable buds on the scion above the graft union is standard practice to ensure there are points for new growth to emerge.
Post-Graft Care and Success Monitoring
Immediately after the graft is completed, the focus shifts to protecting the delicate union and encouraging the scion wood to grow. A common practice is to shield the newly wrapped area from direct sunlight, often by using a small piece of aluminum foil or a sun visor, as excessive heat can hinder the healing process. The most important ongoing task is the diligent removal of any new shoots or suckers that sprout from the rootstock below the graft union.
The rootstock will aggressively try to grow its own branches, which will divert energy and nutrients away from the desired scion wood, leading to graft failure if left unchecked. A successful “take” is indicated by the swelling of the scion buds, typically within a few weeks, followed by the emergence of new leaves and shoots. The wrapping material can be removed once the graft union has visibly healed and the new growth is established (usually after 6 to 12 weeks) to prevent girdling the expanding trunk. If the scion remains dormant or shrivels, the graft has likely failed, signaling the need to attempt a new graft lower down on the rootstock.