A Splice of Life

By Laura McKissack
Photography by Susan Kalergis

It’s a mild, sunny day as a farmer in Onga, a town in the Fukuoka prefecture of Japan, stands in front of a healthy-looking lemon tree and proudly holds out a large yellow fruit for the camera. There’s nothing particularly unusual about this scene, except that this farmer’s single lemon tree happens to bear 10 other kinds of fruit in addition to lemons. Manabu Fukushima has relied on his own skill—as well as the kindness of neighbors who’ve provided him with citrus saplings from their own trees—to create what some might call his very own Frankenfruit tree.

But there are no dungeon labs or genetic modifications involved here. Fukushima is a master at the art of grafting—a process by which a sapling or cutting of one tree, in this case called a “scion,” is wedged into the trunk of another tree referred to as the “root stock.” Utilized for thousands of years, grafting was practiced commonly by the ancient Greeks and Chinese. Without grafting, many edible fruit trees such as cherry and apple would never have been domesticated because they do not naturally pass on those genes which we consider desirable with any consistency. 


Grafting combines the sought-after qualities in the rootstock with the desirable fruits of the scion. For instance, because peach trees grown in Central Texas are prone to damage from nematodes, they are often grafted onto a patented rootstock called Nemaguard. If left to grow unaltered, a mature Nemaguard stock tree would produce fruits that are unrecognizable and inedible, but when the stock is grafted with a peach-tree sapling, the end result is a healthy peach tree that can fight nematode attacks. 

Another reason to graft is to improve the plant’s environmental hardiness. Pecan trees are sometimes grafted onto rootstock that is more cold hardy than the scion plant. Apple trees are often grafted onto dwarfing rootstock. This assures high production without taking up a lot of space, as well as ease of harvest. And in an advantage referred to as “precocity,” a scion grafted onto mature rootstock will get to skip the three or more years of juvenile development that fruit trees usually require before producing a significant amount of fruit. Orchard owners use this trick to replace crops that are aging or to change crops altogether without having to start over from seed. They cut down the old trees to a suitably sized rootstock, then graft on new scion wood. 

There are several ways of grafting, and some are more complex than others. Which method is used depends on what is being grafted, when and why. In citrus, as well as in grapes, the type of graft commonly used is called “T-budding.” The grower shaves an unopened bud from the desired scion plant, then makes a T-shaped cut into the rootstock—exposing the cambium layer between the bark and the wood, where new cellular growth takes place. The grower then fits the bud into the exposed area made on the bark, so that the cambium layers of each plant are connected. He then tapes the wound with grafting tape as closely and tightly as possible without covering the new bud itself. If the graft takes, the new limbs start growing right out of the rootstock. A scion of a successful tree will grow truer to its parent than will a sapling grown from the seed of that tree—much like a clone is closer to its parent than would be a child born from two parents.

The same applies to pecans. “You never know what you’re going to get from a nut,” says Sam Pollard of Texas Pecan Nursery. He explains that if you were to plant any old pecan, it might result in a tree that produces great pecans—or it might not. If, on the other hand, you take a scion from a tree that produces great pecans and graft it onto pecan-friendly rootstock, the result will be a tree that makes the same great pecans. Pollard uses Moore rootstock for the trees he grafts, and the nursery sells both the grafted trees and the rootstock itself, wholesale. They also sell grafting tools, but he says all that’s really needed is a clean, sharp knife, grafting tape, grafting wax (to seal the wound), rootstock and scion wood.

Texas Pecan Nursery uses the complex whip graft primarily for their pecan trees—a process achieved by cutting the rootstock and the scion wood at an angle so that they fit together, then making a downward cut into the face of the original cuts, so that the resulting cut has a lightning-bolt shape. It’s a difficult graft because of how closely the two pieces need to fit together. Pollard says they do this graft from early January until late February. For the home grower, he recommends the slightly less difficult inlay and four-flap methods, which should be done in the spring. All of these methods can be found online, and watching a video or two is helpful in understanding exactly how they’re performed. 

Home grafting may take some trial and error to get right, but it’s a rewarding pursuit and an excellent way to help preserve heritage fruit and nut varieties.

grafting2

RESOURCES

 

Grafting and Budding: A Practical Guide for Fruit and Nut Plants and Ornamentals by Donald McEwan Alexander and William J. Lewis (Landlinks Press, 2009)

Secrets of Plant Propagation: Starting Your Own Flowers, Vegetables, Fruits, Berries, Shrubs, Trees and Houseplants by Lewis Hill (Storey Publishing, 1985)

Texas A&M University-Kingsville Citrus Center provides certified virus-free citrus bud wood at both the individual and wholesale level. Contact John Watson at 956-447-3366 or Mark VanNess at 956-447-3399.

Texas Pecan Nursery: texaspecannursery.com, 903-849-6203

Information on growing citrus plants: aggie-horticulture.tamu.edu/extension/homefruit/citrus/citrus.html

Information and videos on grafting: aggie-horticulture.tamu.edu/propagation/propagation.html