History, Conservation, and Cultivation of American Ginseng, North America’s Most Famous Medicinal Plant

Abstract

Asian ginseng played an integral role in traditional Chinese medicine for millennia, but overexploitation of the plant, coupled with habitat loss, contributed to steep declines in natural populations throughout China. The discovery of the closely related medicinal herb, American ginseng, in Canada in the early 1700s ignited three centuries of trade between North America and China. Profits made from the export of American ginseng to China facilitated western expansion in the United States, and the fortunes of some early Americans were built on the American ginseng trade. American ginseng has been harvested continuously in North America following its initial discovery, punctuated by regional spurts of intense harvest in response to economic needs of rural residents. The ongoing extraction of American ginseng from deciduous forests throughout its range have resulted in modern populations that contain fewer individuals and individuals of smaller stature relative to historic populations, yet thousands of these remnant populations remain. In fact, concerns about overharvest of American ginseng led to its placement on Appendix II of the Convention on the International Trade in Endangered Species of Wild Fauna and Flora (CITES) in 1975. Overexploitation, however, is not the only threat to wild populations of American ginseng. Climate change and browse by overabundant white-tailed deer also negatively affect American ginseng and pose a threat to the future viability of populations. Conservation efforts are needed to ensure that populations of wild American ginseng persist. Population stewardship is a low-labor conservation strategy where individuals promote the growth of wild ginseng populations by strategically planting seeds and removing the aboveground portion of large plants just prior to the onset of harvest season to prevent potential harvesters from locating the adult plants. Another conservation strategy, conservation through cultivation, involves shifting harvest pressure from wild American ginseng to cultivated ginseng. Wild-simulated cultivation is a low-labor technique where seeds are planted into desirable habitat and are left to grow with little intervention until the roots are ready for harvest years later. Wild-simulated cultivation produces roots that are virtually indistinguishable from true wild roots, which makes this type of cultivation a desirable option for the conservation through cultivation approach. Additional cultivation techniques include woods-cultivation, which is ginseng grown in prepared beds under natural forest canopies, and artificial shade cultivation, which is the most labor-intensive cultivation technique and requires large initial investments in shade structures and site preparation. The last two cultivation techniques can produce large roots and abundant seeds in a short period of time. However, the roots lack morphological features desired in traditional Chinese medicine, and are less valuable than both wild-simulated and true wild roots. The abundance and size of wild American ginseng populations are decreasing range-wide, and this negative trajectory is certain to continue unless efforts are made to both improve the management of wild populations and to increase conservation efforts.