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Cypripedium acaule

Common name: pink lady's-slipper

Pink lady's-slipperThis 6 to 15 inch high plant is native to areas east of the Mississippi and from eastern Canada to Alabama and is usually found in forests and woodlands, typically on acidic soils. However, this widespread species can be found in a wide variety of environments, from coastal plains, to pine barrens, to mountaintops. The pink and brown, or, rarely, white and green flower is about 3 inches long. C. acaule requires acidic soil but tolerates a range of shade and moisture, though it prefers at least partial shade and well-drained slopes. In pine forests, it can be seen in large colonies, but it also grows in deciduous woods.


Pink lady's-slipper has been referred to as the “Prozac of the 1800s”, “American Valerian”, and “Mocassan Flower.” Its roots were traditionally used by Native American tribes like the Penobscot and the Cherokee for their sedative, nervine and antispasmodic qualities, including leg spasms, childbirth, mental/emotional nervousness, and hysteria. Other lady’s-slippers are said to have the same applications.


This plant has an extremely long life-cycle, taking many years to go from seed to a mature, seed-bearing plant. The plants can live to be twenty years old or more. Because it will grow only in very specific circumstances, the harvest of wild lady's-slipper root is often not sustainable. Cultivation is also challenging, and the plant has not been widely grown for the medicinal herb market. Cypripedium, along with other orchid species, is listed in Appendix II of the Convention on International Trade in Endangered Species (CITES), making it illegal to export any part of the plant without a permit. In 1988, the American Herbal Products Association issued a self-regulatory initiative for its members requiring them to refrain from trade in wild-harvested Cypripedium. Today, there are only a few companies selling lady's-slipper or products containing lady's-slipper.


C. acaule is difficult to grow in the average garden and is unlikely to survive attempts at transplantation. It has thus far proven nearly impossible to cultivate in a way that would make it feasible as a cash crop. It requires that certain fungal mycelia be present in the soil, so it is almost necessary to grow it in a forested area which either does contain wild lady's-slipper, or is at least the type of environment where it is normally found. Usually this means a wet forest area with dappled shade. Success has been reported in growing lady's-slippers in a controlled laboratory environment, but the cost of this generally makes it unprofitable as a medicinal herb.


Pink lady's-slippers also require bees for pollination. Bees are lured into the flower pouch through the front slit, attracted by the flower’s bright color and sweet scent. Once inside, the bees find no reward, and discover that they are trapped, with only one point of escape. Inside the pouch, there are hairs that lead to a pair of exit openings, one beneath each pollen mass. The bee must pass under the stigma, so if it bears any pollen from a visit to another flower, it will be deposited before picking up a fresh load on the way out.


Find them at Garden in the Woods in: the stockbeds, woodland, rich New England woodland, New England Rare Plant Garden, and Herb Garden

Please note: This article is for historical information use only. New England Wild Flower Society does not advocate the use of any native plants for medicinal purposes.


New England Wild Flower Society is part of the community of non-profits in Framingham, MA, which is collaborating on a town-wide celebration of the role the citizens of Framingham played in the Civil War for the 150th anniversary of that conflict. New England Wild Flower Society will offer several special tours of Garden in the Woods in April and August with particular emphasis on herbal plants used for medicinal purposes during the Civil War. In the fall of 2010, Anna Fialkoff, horticultural apprentice, constructed an herb garden including an herb spiral in the Idea Garden. Her notes are the basis of this series of articles.


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last modified March 11, 2011