Rare Species Guide

  Basis for Listing

In Minnesota, wild populations of Hydrastis canadensis (goldenseal) are currently known only in a few counties in the southeastern corner of the state (The Blufflands, Rochester Plateau, and Oak Savanna subsections). There may also be small cultivated plots or artificially "woods grown" colonies in other southeastern counties. It is clear that H. canadensis has always been rare in Minnesota, in part because southeastern Minnesota is at the northwestern periphery of its North American range. Recently, however, it has become even rarer, not only in Minnesota but across its entire range because of intensive and unsustainable exploitation by commercial root diggers. Root diggers remove the rhizome and the roots, which often kills the plant.

Hydrastis canadensis has significant monetary value in the herbal medicine trade, and "wildcrafting" has a distinct appeal to many people. The rhizomes and roots, which are high in the alkaloid berberine, are traditionally used as an antibacterial to treat sores of the mouth, throat, and digestive system. Currently, there is no evidence that products made from this plant have any medicinal value (Mahady and Chadwick 2001). Hard data on harvest activity in Minnesota are not available, but anecdotal evidence indicates that it does occur. Therefore, the main threat to H. canadensis may be the selective exploitation of the plant itself rather than loss of its habitat. Even though illicit root digging is the main threat, H. canadensis has also experienced a reduction of suitable habitat through residential and road construction, livestock grazing, unsustainable timber harvest, and land clearing for agriculture. However, because of its market value, habitat preservation alone will not secure this species in Minnesota. Hydrastis canadensis was listed as a state endangered species in 1984. This listing precludes harvesting from wild populations.

  Description

Hydrastis canadensis is a slow-growing herbaceous perennial plant that gets no more than about knee-high. Flowering individuals have 1 stem and 2 palmately lobed leaves rising from a yellow underground rhizome. The rhizome is thick and knotted and produces numerous long yellow roots. The single flower is inconspicuous and appears for only a short time in early spring. It is terminal with 3 sepals, no petals, and 12 or more pistils. Flowers develop into a head of crimson raspberry-like, 2-seeded berries.

  Habitat

Hydrastis canadensis occurs in mesic hardwood forests, usually in sheltered ravines or on talus slopes. It appears to be intolerant of grazing or disturbances that open the forest canopy. It is often associated with a rich woodland ground cover of Asarum canadense (wild ginger), Hepatica acutiloba (sharp-lobed hepatica) and Caulophyllum thalictroides (blue cohosh). Populations range from just a few scattered individuals to more than 100 at each site.

  Biology / Life History

Plants produce insect-pollinated flowers in the spring before the canopy trees leaf out. Fruits are formed in late spring-early summer. The rhizome grows at a rate of perhaps 2.5 cm (1 in.) per year and can be up to 7 cm (3 in.) long in old individuals. Over time, the rhizome may fragment and produce a second plant. It has also been reported that it can reproduce via buds on the roots, which can grow up to 1 m (3 ft.) long, and produce new plants (ramets) more than 60 cm (24 in.) from the parent plant (Christensen and Gorchov 2010). This sort of vegetative reproduction, under ideal conditions, can lead to the development of small but dense clones. Flowers are insect-pollinated, and apparently fertile seeds are produced by being self-pollinated or by outcrossing. However, the production of fertile seeds is apparently infrequent. Dispersal within or between habitats is accomplished by seeds spread by animals. The seeds remain dormant over winter, and most germinate the following spring. Some seeds may remain dormant in the soil for one additional year (Christensen and Gorchov 2010). This is a long-lived perennial species adapted to shady habitats and moist soils.

  Conservation / Management

A decrease in undisturbed deciduous woodlands and steady pressure from root diggers has contributed to a decline of H. canadensis throughout its range (Ford 1997). Root diggers may still be actively seeking this plant in Minnesota, subjecting remaining populations to harvest pressure. Any such harvest is illegal, because the endangered species law prohibits the taking of wild H. canadensis for any purpose without a permit from the Minnesota Department of Natural Resources (MN DNR). Major canopy removal or silvicultural treatments that disturb the soil should be avoided near H. canadensis populations.

  Best Time to Search

The best time to search for Hydrastis canadensis is when leaves are fully expanded from May to August.

  Conservation Efforts in Minnesota

Several H. canadensis populations occur on State Park, County Park, Wildlife Management Area, and State Forest lands. Unfortunately, it is difficult to protect plants, even on public land, from illegal harvest.

  Authors/Revisions

Welby R. Smith (MNDNR), 2020

(Note: all content ©MNDNR)

  References and Additional Information

Charette, L. A. 1964. Hydrastis canadensis L. in New England. Rhodora 66(765):94-95.

Christensen, D. L. and D. L. Gorchov. 2010. Population dynamics of goldenseal (Hydrastis canadensis) in the core of its historical range. Plant Ecology 210(2):195-211.

Douglas J. A., J. M. Follett , J. E. Waller, and C. E. Sansom. 2013. Root and rhizome production of goldenseal (Hydrastis canadensis L.) under cultivated conditions in New Zealand. New Zealand Journal of Crop and Horticultural Science 41(1):32-40.

Ford, B. A. 1997. Hydrastis. Pages 87-88 in Flora of North American Editorial Committee, editors. Flora of North America north of Mexico. Volume 3. Oxford University Press, New York, New York.

Inoue, M., K. J. Kelley, A. Frary, and L. E. Craker. 2013. A measure of genetic diversity of goldenseal (Hydrastis canadensis L.) by RAPD analysis. Genetic Resources and Crop Evolution 60:1201-1207.

Mahady, G. B., and L. R. Chadwick. 2001 Goldenseal (Hydrastis canadensis): Is there enough scientific evidence to support safety and efficacy? Nutrition in Clinic Care 4(5):243-249.

Nekola, J. C. 1990. Rare Iowa plant notes from the R. V. Drexler Herbarium. Journal of the Iowa Academy of Science 97(2):55-73.

Rosendahl, C. O., and J. W. Moore. 1947. A new variety of Sedum rosea from southeastern Minnesota and additional notes on the flora of the region. Rhodora 49:197-202.

Sanders, S. 2004. Does breeding system contribute to rarity of goldenseal (Hydrastis canadensis)? American Midland naturalist 152(1):37-42.