American Ginseng

By Richo Cech

This is an excerpt from Richo’s book,Growing At-Risk Medicinal Herbs. Notes on American Ginseng (Panax quinquefolius L.)…As long as the minimum requirements of appropriate temperature, soil and shade are met, some success in cultivating ginseng outside its native range is a reasonable expectation. For example, west of the Rockies the states of Oregon and Washington have proven fertile ground for both home-based gardening and large-scale farming of ginseng. Canada, with its cold winters and dry climate rates third in world production of ginseng. Agriculture and Agri-food Canada reports that over 5,000 acres of American Ginseng were under shade cultivation in Canada in 1996, with production areas concentrated in southwestern Ontario and British Columbia. The majority of cultivated ginseng finds its way to Asian markets, but in a strange twist we have now begun to see Chinese-grown American ginseng entering the U.S. markets. Finally and perhaps most surprisingly, there is a solid and functional group of Australians that are growing Ginseng “down-under” and finding local markets for their products, both fresh and dried.

Ginseng prefers to grow under the shade of a mixed hardwood forest, usually on sloping ground with a northerly or easterly exposure. The degree of shade given to the plants is critical. 70% shade is often considered to be ideal, meaning that at any given time during the day the plants are receiving only 30% of the light that is shining on the uppermost leaves of the trees in the canopy above. This light will strike the plants as filtered light, reflected light and dappled sunlight, moving constantly as the earth revolves and as the trees and leaves sway and shift in the breeze.

Ginseng can also be grown in complete shade, relying only on reflected light, and in certain circumstances it can tolerate more than 30% direct light, especially if that light is hitting the plants during the morning hours. Directional exposure, climate and elevation will certainly influence the effect of light, while the microecology of the planting spot, including companion plants, rocks and trees can readily assist plants to withstand greater amounts of sun than is normally considered ideal. To a certain extent, since the plant uses sunlight to manufacture its food, providing as much light as the plant can comfortably bear will speed growth and produce a larger root. The best soils for ginseng culture are rich in humus, the wholesome product of decomposing leaves and wood. Humus contributes to the growth substrate for the plant, is the most significant source of needed nutrients and also provides a home for soil fungi that are symbiotic with ginseng. (Whitebread, McGonigle and Peterson 1996.)1 The close proximity of large limestone features or smaller limestone rock to sweeten the soil is helpful. In the east, mixed hardwood forests predominated by oak, beech and maples are particularly good for ginseng growing, although any mixed hardwood forest has potential, especially if wild ginseng already occurs in the area. In the west, the best soils are those generated by a mixed maple and alder forest. It is my experience that both oak forests and coniferous forests in the west are poor sites for ginseng culture, but other growers have had success working under these trees. A sandy loam or clayey loam with pH of 5.5 to 6.5 is ideal; heavy loam, sandy soils and clay soils can also be serviceable. The soil must be well drained, either by dint of porosity of structure or because of a steep grade. Ginseng roots will rot in mucky ground.

Examples of plants that grow in close proximity to wild ginseng in the eastern states are black cohosh (Actaea racemosa), bloodroot (Sanguinaria canadensis), goldenseal (Hydrastis canadensis), Solomon’s seal (Polygonatum biflorum), spice bush (Lindera benzoin) and trillium (Trillium spp.). If these plants occur in the woods, it is likely that conditions are right for growing ginseng. Examples of plants that indicate good ginseng growing ground in the west are false Solomon’s seal (Smilacina racemosa), Oregon grape (Mahonia nervosa), trillium (Trillium spp.) and wild ginger (Asarum canadense). In cultivation, it is often preferable to alternate beds of ginseng with other shade dependent herbs in order to approximate the natural forest community of plants. Mono-crops deplete the soil, are subject to disease and generally require constant surveillance and chemical input. Mixed crops consisting of a diversity of species become mutually supportive, reducing the need for human intervention and promoting balanced soil ecology while increasing resistance to disease and pests.

American ginseng is listed in the Convention on International Trade in Endangered Species (CITES) Appendix 11 and global trade in wild-harvested root is regulated. The plant is designated by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC)2 as Threatened in Canada, and no exportation of wild-harvested roots is allowed from Canada. Under the direction of the US Fish and Wildlife Service, individual states in the US where wild ginseng is still found have developed programs to regulate harvest, and harvest is illegal in national parks and many other protected areas. However, government rules can only do so much to protect slow-growing and sensitive wild plants, and because there is an ongoing demand for wild roots, areas where ginseng harvest is legal have been picked out, causing a corresponding increase in poaching from protected areas. (Gagnon, 1999) In the face of this deterioration, it becomes increasingly important to protect and nurture remaining wild populations of ginseng. In replanting the wilds, it is important to use wild-derived, bioregionally cultivated seed in order to preserve any regional variations in the general gene pool. The genetic diversity of distinct wild populations will prove very useful in the future when we seek to breed vigor back into cultivated ginseng. In order to fulfill world demand, it is of paramount importance that we continue to cultivate ginseng. We can rejoice that in the case of organic and woods-grown ginseng, we improve the local environment while contributing to the protection of an endangered plant. Ginseng is truly the most potent example of the value of conservation through cultivation, because without the concerted efforts of growers worldwide, the plant would currently be extinct.

Footnotes:
1 Vesicular-arbuscular mycorrhizae (VAM) are branched, microscopic fungal symbionts that form within the living cells of the ginseng root. The interaction of VAM with the plant root hairs produces a high surface area interface allowing for efficient exchange of nutrients. The plant produces sugars that are utilized by the fungus, while the fungus breaks down nutrients and by means of its extensive hyphal network enhances their absorption into the plant. Beneficial fungi also produce antibiotics that protect the plant from fungal pathogens, which is of particular advantage for the soft, susceptible roots of ginseng.
2 COSEWIC is a committee of representatives from federal, provincial, territorial and private agencies as well as independent experts that assigns national status to species at risk in Canada.

References:
Gagnon, Daniel. 1999. An Analysis of the Sustainability of American Ginseng Harvesting from the Wild: The Problem and Possible Solutions. Final report to the Office of Scientific Authority of the US Fish and Wildlife Service.
Whitbread F., McGonigle T.P. and Peterson R.L. 1996.
Vesicular-arbuscular mycorrhizal associations of American ginseng (Panax quinquefolius L.) in commercial production. Canadian Journal of Botany 74, 1104-1112.
© 2001, Richard (Richo) A. Cech