1. Family: Ranunculaceae Juss.
    1. Genus: Actaea L.
      1. Actaea racemosa L.

        An attractive woodland plant native to Northern America, black cohosh is commonly grown as a garden ornamental in temperate regions. It is the source of several medicines traditionally used by native North Americans as well as early European settlers, and is a globally popular herbal remedy for treating the symptoms of menopause.

    [KSP]

    Kew Species Profiles

    General Description

    An attractive woodland plant native to Northern America, black cohosh is commonly grown as a garden ornamental in temperate regions. It is the source of several medicines traditionally used by native North Americans as well as early European settlers, and is a globally popular herbal remedy for treating the symptoms of menopause.

    It is almost exclusively harvested from the wild, hence black cohosh has been the subject of some concern for conservationists and regulators as the global demand for products containing this herb increases. The popularity of black cohosh is also having an impact on other species of Actaea and similar plants, which are sometimes confused with black cohosh or intentionally substituted by unscrupulous traders.

    Species Profile
    Geography and distribution

    Black cohosh grows primarily on the moist, fertile slopes of deciduous woodlands along the eastern United States and southeastern Canada. It has a broad distribution, which overlaps with those of several other American Actaea species.

    Various species of Actaea , including black cohosh, are cultivated as ornamentals in partially shaded or woodland gardens in temperate regions.

    Description

    Overview: An attractive clump-forming herbaceous perennial that can reach a height of 2 m or more. The plant produces tall, narrow spikes of small, white flowers that have a tendency to bend slightly towards the sun.

    Leaves: The leaves are compound (divided into many smaller leaflets). The leaflets are usually mid to dark green and toothed, with 2-5 sets branching out in groups of three along the petiole (leaf stem). Individual plants may have as few as just one or two compound leaves of up to 60 cm in length. Clumps can become sizeable over time.

    Flowers: Tall flower stems branch into several long, narrow racemes (flower spikes) of small creamy-white flowers from June to September. These appear as a cluster of stamens (male parts) surrounding the stigma (female part) with no petals or sepals apparent. They have a mildly foetid smell that attracts flies as pollinators.

    Fruits: Black cohosh produces what are known as follicles, on short stalks along the flower stem. These are dry fruits that develop from each flower and split open across the top and down one side to reveal the seeds.

    Seeds: Each follicle contains two rows of tiny, smooth, brown seeds - similar in shape to the segments of an orange.

    Actaea or Cimicifuga?

    Swedish botanist Carl Linnaeus published the name Actaea racemosa in Species Plantarum in 1753.

    On noting the marked difference between the dry follicles produced by black cohosh and the bright fleshy fruits of some other Actaea species, British-American botanist Thomas Nuttall moved this plant to the genus Cimicifuga in 1818.

    There it remained, as Cimicifuga racemosa , until 1998 when scientists studying the entire group concluded that, in spite of the differing fruits, the genera Actaea and Cimicifuga are so genetically similar that they should not remain separate.

    Hence black cohosh is often known by the synonym Cimicifuga racemosa , which was considered the correct scientific name for this species until relatively recently.

    Threats and conservation

    For medicinal purposes it is usually the rhizome (underground stem) of black cohosh that is used and so the entire plant must be dug up in order to harvest the medicinal part. Black cohosh is almost exclusively harvested from the wild, and global demand has been increasing over time with over 40 million plants harvested for the international marketplace between 2000 and 2010. To add to this, plants grown from seed can take as long as three to four years before they flower and even longer before the rhizome reaches a reasonable size for harvesting, which places a further strain on wild populations and makes cultivated black cohosh products more expensive.

    Although not currently listed on the IUCN Red List of Threatened Species, black cohosh has been the subject of ongoing monitoring by the United States Fish and Wildlife Service and the US Forest Service due to reports that local populations are in decline. Growing international trade has been identified as the primary threat, although habitat loss may also be an issue in some areas. In particular, reports suggest that black cohosh is threatened in the states of Massachusetts and Illinois, but limited data regarding other regions, as well as inconsistencies in data collection over time, means further assessment is required for Actaea racemosa in order to safeguard its future.

    A proposal to include Actaea racemosa in Appendix II of CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora), which aims to protect species from over-exploitation, was rejected in 2002 and further review recommended.

    Uses Traditional medicine

    Black cohosh rhizome was traditionally used by a number of Native American tribes, including the Cherokee and Iroquois, for a broad range of complaints including rheumatism and tuberculosis and as a gynaecological aid.

    In modern Western herbal medicine, use of black cohosh is generally limited to treating the symptoms of menopause and other complaints of the female reproductive system, but application across a much broader range of disorders, including arthritis and tinnitus, is still supported by many. Black cohosh was noted as one of the five top selling over-the-counter herbal remedies in the United States in 2013.

    Ornamental

    Black cohosh is particularly prized for its clump-forming habit and tall spikes of creamy-white flowers that stand out in a woodland garden setting. It has received a Royal Horticultural Society (RHS) Award of Garden Merit.

    Cultivation

    Black cohosh is fairly easy to grow in a cool, partially shaded border or woodland garden. The soil should be moist with plenty of organic matter, although black cohosh can also be grown in slightly more rocky settings.

    The quickest method of propagation is to divide the rootstock of a large clump in early spring, ensuring that each piece of rhizome includes at least one bud. Propagation by seed is also possible, although plants grown in this way will take longer to reach flowering.

    Black cohosh at Kew

    Black cohosh can be seen growing at the edge of Kew's Woodland Garden (near the south end of the Princess of Wales Conservatory).

    Several historical and more recent samples of dried black cohosh rhizome are held in Kew's Economic Botany Collection. Specimens like these are often used as benchmarks to aid in the identification, analysis and authentication of herbal products and raw materials found in trade. These samples are available to researchers by appointment.

    Preserved specimens of Actaea racemosa are held in Kew's Herbarium where they are available to researchers by appointment. Images of some of these specimens are available online in Kew's Herbarium Catalogue.

    Black cohosh and Kew's Medicinal Plant Names Services project

    Medicinal Plant Names Services (MPNS) is a Kew project working with herbal regulators, traders and practitioners to clear up confusions surrounding plant names for the broader benefit of the general public.

    For example, although black cohosh ( A. racemosa ) is used to treat the symptoms of menopause, three species of Actaea from Asia ( A. cimicifuga , A. dahuria and A. heracleifolia ) are used in Traditional Chinese Medicine for very different complaints, such as toothache and diarrhoea. The problem is that all these species are referred to by the same pharmaceutical name 'Cimicifugae Rhizoma' in some important medicinal literature. In addition, because pharmaceutical names like this one are written in Latin, they can be easily confused with scientific plant names leading to misunderstandings about which species is being referred to.

    This poses potentially serious problems in trade and medical practice since it means herbal products with different chemistry are easily mixed-up or misused unless the correct scientific name of the plant involved is included in literature and on labelling. Kew's MPNS are helping the industry deal with problems like these by providing services to link accepted scientific names with as many common, drug and pharmaceutical names as possible. One of these services is a searchable online portal.

    Search the Medicinal Plant Names Services portal

    Distribution
    Canada, USA
    Ecology
    Moist, partially shaded woodlands and rocky thickets of eastern North America.
    Conservation
    Global NatureServe Status: G4 (apparently Secure), however assessed as N2 (imperilled) in Canada and S1 (critically imperilled) in Massachusetts and Illinois.
    Hazards

    Herbal medicines containing black cohosh are generally regarded as safe if taken as directed. Though poorly substantiated, some serious adverse reactions to black cohosh have been reported.

    [KSP]
    Use
    Medicinal, ornamental.

    Images

    Distribution

    Native to:

    Alabama, Arkansas, Connecticut, Delaware, District of Columbia, Georgia, Illinois, Indiana, Kentucky, Maryland, Masachusettes, Missouri, New Jersey, New York, North Carolina, Ohio, Ontario, Pennsylvania, South Carolina, Tennessee, Virginia, West Virginia

    Common Names

    English
    Black cohosh

    Actaea racemosa L. appears in other Kew resources:

    First published in Sp. Pl.: 504 (1753)

    Accepted by

    • Bailey, C. & al. (2015). Guide to the Vascular Plants of Tennessee: 1-813. University of Tennessee press.
    • Mohlenbrock, R.H. (2014). Vascular Flora of Illinois. A Field Guide, ed. 4: 1-536. Southern Illinois University Press, Carbondale.
    • Govaerts, R. (1995). World Checklist of Seed Plants 1(1, 2): 1-483, 529. MIM, Deurne.

    Literature

    Kew Species Profiles
    • Anon (Updated 2015). Natural Heritage & Endangered Species Program: Black Cohosh Fact Sheet. Massachusetts Division of Fisheries & Wildlife.
    • Davis, J. (2013). Black Cohosh (Actaea racemosa L.). Extension: WNC Natural Products Project.
    • Small, E. & Catling, P. M. (2013). Canadian Medicinal Crops: Cimicifuga racemosa (L.) Nutt. (Black Cohosh). Agriculture and Agri-Food Canada.
    • Pengelly, A. & Bennett, K. (2012). Appalachian Plant Monographs. Black Cohosh Actaea racemosa L. Appalachian Center for Ethnobotanical Studies.
    • Southern Cross Plant Science (2012). Medicinal Plant Monographs: Actaea racemosa. Southern Cross University, Australia.
    • Brinkmann, J. (2010). Taking a closer look at the US black cohosh rhizome trade. HerbalEGram 7(12). American Botanical Council.
    • Painter, D., Perwaiz, S. & Murty, M. (2010). Black cohosh products and liver toxicity: update. Canadian Adverse Reaction Newsletter 20(1): 1–2. Health Products and Food Branch, MedEffect, Canada.
    • Lonner, J. (2007). Medicinal Plant Fact Sheet: Cimicifuga racemosa / Black Cohosh. A collaboration of the IUCN Medicinal Plant Specialist Group, PCA-Medicinal Plant Working Group, and North American Pollinator Protection Campaign. PCA-Medicinal Plant Working Group, Arlington, Virginia.
    • Lyke, J. (2001). Summary of the Conservation Status of Cimicifuga  ssp. (Cimicifuga rubifolia C. americana , and C. racemosa ). Plant Conservation Alliance Medicinal Plant Working Group.
    • Robbins, C. (1999). Medicine from U.S. Wildlands: An Assessment of Native Plant Species Harvested in the United States for Medicinal Use and Trade and Evaluation of the Conservation and Management Implications. TRAFFIC North America.
    • Compton, J. A., Culham, A. & Jury, S. L. (1998). Reclassification of Actaea to include Cimicifuga and Souliea (Ranunculaceae): phylogeny inferred from morphology, nrDNA ITS, and cpDNA trnL-F sequence variation. Taxon 47(3): 593–634.
    Kew Backbone Distributions
    • Mohlenbrock, R.H. (2014). Vascular Flora of Illinois. A Field Guide, ed. 4: 1-536. Southern Illinois University Press, Carbondale.

    Sources

    Kew Backbone Distributions
    The International Plant Names Index and World Checklist of Selected Plant Families 2018. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    [A] © Copyright 2017 World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

    Kew Names and Taxonomic Backbone
    The International Plant Names Index and World Checklist of Selected Plant Families 2018. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    [B] © Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

    Kew Species Profiles
    Kew Species Profiles
    [C]
    [D] http://creativecommons.org/licenses/by-nc-sa/3.0