Nurseryman and plant explorer Daniel J. Hinkley speculates on how we’ll be gardening
illustration byADAM ROGERS
THIS IS A HEADY TIME IN AMERICAN HORTICULTURE. For the last two centuries, gardening in this country has been marked by a steep learning curve and a search for our own identity; at last, however, American gardening has come of age. It will be fascinating to see where our pluck and resourcefulness take us as we move forward, no longer subservient to the traditions of Europe and Asia, but embracing what our gardens can be. Over the last 20 years, I’ve had the opportunity to meet many keen gardeners throughout North America and Europe, and have observed how interest in plants and design has changed; here, however, I offer only my informal and very personal perceptions of where gardening may be heading in the century ahead.
THE ROLE OF WOODY PLANTS The increase in leisure time and the rise in affluence over the past century have led us from the utilitarian vegetable garden to the cultivation of plants for pleasure. This interest in plants for their own sake has, in turn, progressed from an engrossment in houseplants and annuals to a fascination with ornamental grasses and herbaceous perennials. Logically, it would seem that the next step would be into the bush, so to speak—that is, toward a greater appreciation and integration of woody plants in the American landscape. These structural elements of the garden are now poised to command as much attention as less-permanent plants.
This trend is evident in the growing interest in woody plant breeding and selection, which has already yielded shrubs and trees for the smaller urban garden that are sturdier and more appealing than the raw goods of nature. Our growing ability to analyze the close genetic relationships between plant species will allow even more inventive breeding work in the future.
Some of the most exciting work in ornamental plant breeding in this country is being conducted by Dr. Tom Ranney and his talented colleagues at the Mountain Horticultural Crops Research and Extension Center of North Carolina State University in Fletcher, North Carolina. This year, for example, the Center will be releasing Calycanthus ‘Venus’, a complex hybrid between Calycanthus floridus, C. occidentalis (both North American species), and a relatively new arrival from China, C. chinensis. The sensational result of this menage a trois is a deciduous shrub that offers a long season of large, fragrant, magnolia-like flowers of white suffused with purple. Also under evaluation for possible future release are a bevy of other innovative bigeneric hybrids, which have been bred with an eye to improved disease resistance and landscape adaptability. Among this group are crosses of Franklinia x Schima, Pyrus x Malus, Pyrus x Chaenomeles, and Aronia x Sorbus.
AN ONGOING QUEST
Annuals are another group that could profit greatly from more enlightened breeding goals. It would be gratifying to see a return to wilder-looking, more graceful, and more fragrant annuals, rather than the soggy lumps of vegetable matter they have morphed into for increased ease of production and marketing. I’d much rather have a willowy nicotiana that envelops the evening garden in a fragrance that makes one want to stay just a bit longer.
Much future breeding work, whether in the realm of woody or herbaceous plants, will depend on continuing plant exploration and the desire to understand the earth’s diverse flora. With the 21 st-cen-tury world such a seemingly small place, it’s tempting to conclude that the entirety of plant species worthy of ornamental or agricultural use has already been discovered and introduced. Nothing could be further from the truth.
“In gardening… there should be as much room as possible for experimentation, and next to none for dogma.”
The increasing ease of travel, along with the opening of hitherto inaccessible areas, will result in the complete reevaluation or rediscovery of species (especially those originally from higher elevations and more extreme latitudes) that were previously introduced and subsequently lost. Moreover, there still exists a staggering number of plants that have yet to be discovered or brought into cultivation. These species are not necessarily from remote regions of the globe. In the early 1990s, for example, a tall deciduous shrub in the rose family, now called Neviusia cliftonii, was discovered growing alongside Route 299 near Redding, California. Previously known only through fossil evidence, it is a reminder that there are discoveries still to be made in our own backyards.
Along with the increased availability of new species, I believe there will be greater efforts to prevent the escape of garden plants into our native ecosystems. The days of thoughtlessly abandoning a fish, bird, or plant to the wild and hoping for the best are thankfully over. The old saying, “closing the barn door after the horse has bolted,” is sometimes used to justify the wholesale introduction of new plant species without considering their potential for bioinvasion. But this misses the point. Though this debate remains exceedingly complex, no one wants additional exotic plants displacing native species already under severe pressure from habitat loss.
The solution, I believe, will ultimately come from plant selection and breeding, with sterile or less fertile selections becoming the norm rather than the exception. This isn’t the same thing as genetic engineering—at least not the kind of genetic modification that has caused so much heated controversy in recent years.
Naturally occurring tetraploids—that is, plants possessing double the normal number of chromosomes—are found in almost all plant populations. When these tetraploids are crossed with their ordinary diploid kin, the resulting progeny are triploids, which are either completely sterile or have greatly reduced seed fertility.
This approach is far from novel—human beings have been consuming triploid bananas, apples, and watermelons for decades. What is new is the use of more refined techniques to identify polyploidy in ornamental plants and the development of sterile lines. Research in this area is already in full swing, with Tom Ranney again leading the way. Among the first plants that Ranney and his colleagues have targeted are those with a proven local record of bioinvasion: Albizia julibrissin, Berberis thunbergii, Hypericum spp., Koelreuteria paniculata, and Ligustrum japonicum. Polyploids within these genera have already been identified, and breeding is now under way to create new introductions with a greatly reduced proclivity for wayward wandering. These efforts—made by dedicated scientists who also love the simple pleasure of gardening—represent the union of commonsense thinking with new technologies, and are resulting in the kind of innovative solutions that American gardening needs.
GARDENING WITH NATURE
What about the way gardens are conceived and designed? Historically, Western horticulture has evolved from rigid formality to a more relaxed and natural approach. My guess is that this trend toward greater naturalness will continue to evolve into a more highly organized movement.
The school of thought that sees the primary goal of gardening as the re-creation or reinterpretation of natural plant communities is rapidly gaining momentum. This development is charged with the same kind of energy that must have accompanied William Robinson’s and Gertrude Jekyll’s shift away from the highly contrived bedding schemes of the Victorian period, or Jens Jensen’s embrace of regional influences in this country. More than simply planting in a naturalistic style, this approach engages in an artful conversation with the systems of nature. And as might be expected, it also advocates a greatly reduced dependency on irrigation and chemicals. This aspect of the movement seems prophetic, for in the future the overconsumption of natural resources may prove to be not only unethical but illegal. Yet in gardening, as in any other art form, there should be as much room as possible for experimentation, and next to none for dogma. The spirit of creativity will always be able to transport us to a new and exciting physical and emotional space.
I’m not enough of a visionary to predict what gardening might be like 100 years hence. I imagine, however, that there will be the same excitement and respect that have always characterized those who tend the land. After all, the essence of gardening is changeless and timeless—the satisfaction of a perfectly plucked weed, the pride that comes from the first ripe tomato, the pause we take in our chores to appreciate the marvel we have created. H