by Justin Wexler and Anna Plattner
American ginseng (Panax quinquefolius) loves shade but not too much shade. After seven years of direct observation of hundreds of acres of wild-simulated and wild ginseng, we’ve noticed a pattern. Old wild ginseng plants growing in deep shade grow extremely slowly. Likewise, in full shade, the wild-simulated seedlings of our ginseng plantings become stunted. Without brief periods of direct sunlight or full days of very bright indirect light, our plants look like seedlings for three years or longer, and they may not produce fruit for ten years or longer. In contrast, wild-simulated ginseng plants growing under canopy gaps frequently flower and fruit at three years of age. None of this is a surprise, of course; years of peer-reviewed studies have looked at the positive response of most forest understory plants to canopy gaps. This research has revealed what our ancestors already knew for millennia—even shade plants love a little boost in sunlight.
In American Ginseng Pharm’s large wild-simulated ginseng plantings, which are spread out over a large swath of eastern New York State, we have plenty of opportunities to get to know American ginseng. Wild-simulated cultivation is a method in which ginseng seeds are planted in suitable forest habitat, under the leaf litter, with no tilling, soil amendment, or treatment with chemicals at any point over the life of the plant. It mimics the lifecycle of wild plants, and the end result is healthier plants and a healthier ecosystem. Our interest in understanding the variables that affect the growth of wild and wild-simulated American ginseng borders on obsession. To sustainably grow wild-simulated ginseng on a commercial scale, we have to become intimately familiar with what forest conditions are most conducive to healthy, yet fast-growing, ginseng plants.
When we began planting seven years ago, we would never have dreamed of cutting down a large tree. The mature woods where we planted had a forest floor full of ginseng companion plants. The healthy high and multi-layered canopy provided what we believed was sufficient dappled light. During site preparation we limited our cutting to sapling-size trees that we could cut with pruners and loppers. But our ginseng grew very slowly, and we soon observed that productive plants receive short periods of direct sunlight. One of our managers at the time, Jamie Gillespie, who now runs his own innovative agroforesty operation, recommended that we experiment with altering the light regime through careful thinning of trees. As the sun moves through the sky, this provides an even layer of bright filtered light through sunflecks, a concept explored in recent research (Wagner & McGraw, 2013). Carefully thinning the canopy mimics the lighting created by the natural disturbances of an old-growth forest, such as blow-downs and branch breakage from wind, ice, lightning strikes, and old age. This beneficial cutting results in a healthier forest community and much faster growth in our ginseng plantings. But there are also bad ways to cut trees.
Throughout the Northeast, selective timber cuts are a problem. These logging jobs unintentionally create large, even-aged patches of a small species of a native understory tree, the striped maple (Acer pensylvanicum). These thickets produce a dense shade that is severely limiting to herbaceous species diversity, including ginseng. We have also seen stunted growth of wild ginseng plants found growing in dense thickets of young American beech (Fagus grandifolia) trees, a habitat that is locally called, among other epithets, beech hell. As a result of beech bark disease, which is slowly killing American beech trees throughout the Northeast, the parent trees send up suckers and create practically impenetrable thickets. Such thickets are also created by selective, or high grade, logging jobs. “Beech hell” produces a dense shade that, over time, leads to a forest floor nearly devoid of native understory plants, including American ginseng.
This is ironic: the logging jobs that bring in so much sunlight also create too much shade. And major disturbance by poor timber operations is known to cause a long-term decrease in wild ginseng populations (Chandler & McGraw, 2015). The area affected by logging operations in the Catskill Mountain region is vast and barely noticeable until you step into the forest. The extent of logging has limited many of our wild-simulated ginseng plantings to recently logged forests, making our job in providing the optimal environment for wild-simulated ginseng much trickier and more time-consuming. It is particularly difficult to create ideal wild-simulated growing conditions in the mess of sun and shade of recently logged land.
Through observation and experimentation, we have learned how to carefully choose and cut unhealthy or overcrowded trees to create the perfect light regime for both our ginseng and for wild companion plants. At the same time, we remove invasive species and carefully choose our cuts to maintain native tree species diversity. Our method of gentle thinning is supported by recent research on canopy disturbance. Ginseng growth and the growth of associated plant species increase following disturbances and boosts in sunlight (Chandler & McGraw, 2017). However, a gap that is too small may have little effect on the understory plant community, while a huge canopy gap may destroy it, burning the tender leaves of established ginseng plants and killing ginseng seedlings. In contrast, the optimum canopy gap increases biodiversity and forest health (Kern et al, 2014), and the results can be dramatic, as the forest understory transforms into a sea of lush, green native perennials, a veritable carpet of American ginseng, blue cohosh (Caullophylum spp.), wild leeks (Allium tricoccum), Christmas fern (Polystichum acrostichoides), bloodroot (Sanguinaria canadensis), and other forest botanicals.
Our alteration of the landscape to sustainably produce medicines and to encourage biodiversity is not without precedent. Native people have beneficially altered the environment around the globe—including in our region—with prescribed burns and shifting cultivation for many thousands of years. In Eastern North America, the boost in sunlight by mimicking natural disturbance not only increases biodiversity, but also makes edible fruit-bearing plants, such as the red mulberry and the pawpaw, produce larger yields of sweeter fruit. Some medicinal understory plants, such as black cohosh (Actaea racemosa) and American spikenard (Aralia racemosa), stay small for many years in dense shade, awaiting the creation of a sunny canopy gap so that they can grow much larger and finally bloom and fruit.
These species are likely pre-adapted to take advantage of sudden influxes of light, and American ginseng seems to be among them (Chandler & McGraw, 2017). We find that healthy wild-simulated ginseng plants require a light regime that is around 70% shade, a stark contrast to the 80-90% shade that is often recommended to new growers. To better understand the direct eff ects of the light regime and other variables on our wild-simulated ginseng, we have partnered with Karam Sheban, a master’s student at Yale University. He has made dozens of research plots in our wild-simulated plantings as part of a study that will quantify the importance of the many environmental variables that aff ect the health and growth of wild-simulated American ginseng, including light.
We hope that the next seven years of cultivation and observation will lead to new and better methods for cultivating wild-simulated ginseng sustainably on both the small and large scale. For landowners with forested parcels, wild-simulated ginseng cultivation is likely the only economically-sustainable alternative to a bad selective logging job. Wild-simulated cultivation will also take the burden off of over-harvested wild ginseng populations. We hope that our experience with wild-simulated ginseng cultivation will prove useful and encouraging to other forest farmers interested in growing this ancient plant.
Anna Plattner, general manager of American Ginseng Pharm, and Justin Wexler, co-manager and manager of the company’s medicinal herb farm, live in the Hudson Valley of New York State. When not cultivating wild-simulated ginseng, Anna and Justin teach classes on forest farming, lead walks on native land use and folklore, and assess properties as part of their independent company, Wild Hudson Valley. Outside of work, Anna and Justin steward the diverse ecosystems of their ninety-acre United Plant Savers-certifi ed botanical sanctuary in Cairo, NY. Justin is the author of “Identifying Ginseng Habitat,” a guide to the plant species associated with wild ginseng. Anna and Justin can be contacted through www.wildhudsonvalley. com, and more information about American Ginseng Pharm can be found at www.americanginsengpharm.com.
- Chandler, J.L. & J.B. McGraw (2015). Variable effects of timber harvest on the survival, growth and reproduction of American ginseng (Panax quinquefolius L.). Forest Ecology and Management. 344: 1-9.
- Chandler, Jennifer L. and James B. McGraw (2017). Demographi stimulation of the obligate understory herb, Panax quinquefolius L., in response to natural forest canopy disturbances. Journal of Ecology. 105: 736-749.
- Collins, Beverly Shawna and S.T.A. Pickett (1988). Response of herb layer cover to experimental canopy gaps. American Midland Naturalist. Vol. 119, No. 2 (Apr): 282-290.
- Kern, Christel C., Rebecca A. Montgomery, Peter B. Reich & Terry F. Strong (2014). Harvest-created canopy gaps increase species and functional trait diversity of the forest ground-layer community. Forest Science. 60(2): 335-344.
- Wagner, Alixandra & James B. McGraw (2013). Sunfl eck eff ects on physiology, growth, and local demography of American ginseng (Panax quinquefolius L.) Forest Economy and Management. 291: 220-227.