At this time of the year, we when might enjoy a snow flurry, we have instead a flurry of garden catalogs.
The seasonal catalogs feature the latest crop of floral and vegetal hybrids. The latest creations are always interesting, but I generally prefer the more reliable species.
For the first time this year, The Territorial Seed Company is offering something really different: grafted vegetable plants. All are in the same genus Solanum, known as the nightshades: one eggplant variety (Prospero, an Italian heirloom), six single tomato varieties, and two double tomato varieties, i.e., with two varieties grafted on one rootstock.
Territorial Seeds states that grafted vegetable plants are superior to non-grafted plants in several ways. They produce larger crops of higher quality, resist diseases more effectively, have greater more vigor, etc. They can be planted earlier and harvested over a longer period, and require less treatment with pesticides.
Grafting involves splicing a shoot (the “scion”) from one plant to the rootstock (the “stock”) of a compatible plant. The rootstock is selected for desirable traits, e.g., disease resistance, overall vigor, and the like. Likewise, the scion is selected for stems, leaves, blossoms or fruits that the grower prefers. By combining the traits of the scion and the stock, the grower intends to produce a superior plant.
Grafting, a form of asexual propagation, is a fast alternative to hybridizing, which involves sexual propagation of two compatible plants to create a desirable combination of their traits.
Many grafted plants are available to the home gardener. Dwarf apple trees, for example, are usually grown by grafting the scion of a favored variety to the stock of a dwarf variety. The most popular rootstocks are the M26, which produces dwarf trees, 10 12 feet high, and the M7A, which produces semi-dwarf trees, 14 – 16 feet high.
As another example, roses are often sold as grafted varieties, which typically grow faster and more vigorously than “own root” roses. By comparison, roses grown on their own roots are more true to their variety’s traits and growth habit, hardier and longer lasting. The popular rootstocks for hybrid roses are Rosa multiflora (the “Japanese rose”) and Rosa canina (the wild “dog rose”).
Grafted roses, it must be noted, also have a tendency to sucker, i.e., the rootstock sends up a cane of its own, with leaves and flowers that differ from the grafted variety.
A friend once showed off a rose plant that delighted her by providing both white and red blossoms, not realizing that she had a sucker in flower. That’s not a problem, except that the cane from the rootstock draws energy from the grafted variety and invariably produces inferior blossoms. For these reasons, suckers should be torn from the rootstock (not clipped) when they are noticed.
Despite the familiarity of grafted fruit trees and roses bushes, grafted vegetables are still new to me. When I dug into the topic, I discovered that Asian growers have grafted vegetable plants for hundreds of years to increase plant vigor and productivity, and reduce susceptibility to disease. The technique was introduced into the United States about twenty years ago. Growers that sell to home gardeners have only recently begun to offer grafted vegetables. If grocery stores are selling vegetables grown on grafted plants, they are not labeling them as such. Many people want genetically engineered (“GE”) vegetables to be labeled, but might not be as concerned about grafted vegetables.
Japanese companies have developed robots to reduce the cost of grafting. The process requires careful handling of the young shoots, but can be reduced to instructions to a machine. Robotic grafting machines can produce up to 900 grafts per hour, but they require two or three workers to assist the machine.
If you are interested in trying something new in your vegetable garden this year, you might try a grafted tomato, to see if it lives up to its promises. Territorial Seeds apparently does not yet have a robotic grafter, so it offers hand-grafted plants. The price is $7.50, which is twice the price of an “own root” tomato of the same variety. Buying seeds is of course much less expensive per plant.
Check it out at www.territorialseed.com (look for “Grafted Vegetable Plants” under the “Live Plants” menu).
Even though this technique is quite old in some parts of the world, the introduction of grafting equipment could lead to a growing selection of grafted floral and vegetal “super plants” that are bigger, faster, sturdier, healthier and otherwise behave like products of the modern era.
Enjoy your garden!