Actaea racemosa

Black cohosh, or Actaea racemosa according to Weakley et al. (2024) and Kartesz (1999), is also widely known as Cimicifuga racemosa (Flora of North America 1997). Phylogenetic analyses of Compton et al. (1998) support the inclusion of Cimicifuga within a monophyletic Actaea. Ramsey (in FNA 1997, vol. 3) considers var. dissecta a form of uncertain taxonomic significance and the variety is not recognized as distinct by Weakley et al. (2024). Actaea racemosa can be distinguished from the Appalachian species A. podocarpa (syn. Cimicifuga americana) by the lack of a deep, broad groove on the upper side of lowest petiole (leaf stem). When infertile, Actaea racemosa can be easily confused with Actaea pachypoda, Aruncus dioicus, and Astilbe biternata, as well as other species of Actaea or Cimicifuga.

Black cohosh has a wide range in eastern North America and is particularly abundant in the central and southern Appalachians. It is frequently encountered in a wide variety of wooded habitats across its range. The species is threatened by the general habitat degradation of eastern forests. More significantly, black cohosh is threatened by continuous wild harvest for the medicinal plant industry. Products derived from the dried roots and rhizomes of black cohosh generate over 35 million US dollars annually in retail sales. The vast majority of black cohosh is wild collected since there are no significant sources of cultivated material. This species has been identified as a priority for conservation by many entities including the United Plant Savers, the American Herbal Products Association, the US Forest Service, and the US Fish and Wildlife Service. The conservation status of this species, despite its relative abundance, reflects population declines inferred from continued collection pressure. Comprehensive and systematically sampled population data from across the species' range are needed to quantify current population levels and severity of threats, as well as to prioritize conservation action where it is most needed.

Black cohosh occurs in the eastern United States from New York south to Alabama and west to Arkansas and Missouri. It also occurs in the southeastern tip of Ontario, Canada (Flora North America 1997, Global Biodiversity Information Facility (GBIF) 2020, iNaturalist 2020). The main part of the range includes the central and southern Appalachians in West Virginia, the western part of Virginia, Kentucky and Tennessee.

Accurately estimating the number of occurrences is difficult because the species is widespread and not comprehensively monitored or collected.

The primary threat to black cohosh is the wild harvest of rhizomes and roots for the medicinal plant industry. The majority of wild harvest occurs in the central and southern Appalachians (Kruger et al. 2020). In addition to the harvest pressure, habitat conversion and development are significant direct threats, as is common throughout unprotected areas of eastern forests (Homoya pers. comm., Pittman pers. comm., Kunsman pers. comm., Pearson pers. comm., Frye pers. comm.). Other significant threats include habitat fragmentation and displacement by exotic species (Homoya pers. comm., Penskar pers. comm., Frye pers. comm.).

The market demand for black cohosh has resulted in continued wild harvest over the past two decades, and likely previously (Kruger et al. 2020, Small and Chamberlain 2018, AHPA 2012, pers. comm. M. McGuffin). In 2015, the total retail value for black cohosh was over 35 million US dollars, sourced from an estimated 120,207 kg of dried rhizomes and roots. Despite the high retail value of black cohosh, only a small fraction was paid to harvesters for raw material. Harvesters were paid a total of $957,237, averaging of $7.96 per dried kilogram (Kruger et al. 2020, amounts in US dollars and averaged over 2014 between 2015). The price per kilogram of black cohosh is much lower than other species in the same geographic area such as False unicorn root, Chamaelirium luteum ($158.71 per kg) and Virginia snakeroot, Aristolochia serpentaria ($186.23 per kg, Kruger et al. 2020). The lower price per kilogram and overall volume of black cohosh harvest is an indication that it is still relatively easy to find.

Harvest not only impacts existing populations, but also affects the regrowth of those populations. Populations occurring in the central and southern Appalachians, where the species is most abundant and where harvest intensity is highest, are most affected. The immediate effects of harvest include reduced reproduction and growth, both above and below ground (Small and Chamberlain 2018). In a three year study, populations with intense harvest rates (66%) resulted in an 80-90% decrease of foliage and stem density compared to pre-harvest rates (Small and Chamberlain 2018). With moderate harvest rates (33%), foliage decreased by 70-80%, and stem density by 65% from pre-harvest rates. Significant differences between the non-harvested control plots and harvested plots remained evident two years after the study (Small and Chamberlain 2018). The dramatically reduced population regrowth in harvested populations may have lasting consequences to the long-term survival of those populations (Small and Chamberlain 2018).

No large scale cultivation exists for this species (Suggs pers. comm.). Between 1999 – 2010 only between 1 – 5% of black cohosh entering the herbal market was from cultivated sources, based on the self-reporting American Herbal Products Association (AHPA 2012). Demand is high for forest farmed (also called woods-grown) or wild sources due to purported medicinal benefits of slow growth in wild conditions (Corbin pers. comm.). Attempts are being made to cultivate this species on forest farms in Iowa, Kentucky, and Virginia for the medicinal trade (Halvorsen pers. comm., Blakley pers. comm.).