Comments: This species is threatened by plant collectors (presumably for gardens) and by habitat loss within parts of its range.
Of the several varieties of Cypripedium, C. calceolus var. parviflorum is the usual source for dried roots (Frontier Co-op 2000). After an industry resolution was passed in 1988 to discontinue sales of wild-collected lady's slipper root, many responsible herb companies complied. However, some companies persist in selling it (Frontier Co-op 2000). In addition, although many herb companies have agreed not to sell any Cypripedium material, some large companies continue to pay root diggers for rhizomes (Robyn Klein pers. comm.).
This species is reportedly very difficult to cultivate. It is "considered to be a semi-parasitic species and must be grown in very controlled conditions and is not economically feasible." (Ed Fletcher pers. comm.). Recently, the native plant nursery industry has successfully propagated it and considers it not technically difficult to grow in gardens (Rolf Schilling pers. comm. 2007).
Many orchid species have a reputation for difficulty of cultivation, which may be one reason that wild populations tend to be targeted for harvesting. An internet site contained the following general information on this species: "While commercially propagated plants are available, the quantities and prices do not support cultivation for the dried herb market. Dried lady's slipper roots currently being sold are likely wildcrafted roots, roots of other plants, or roots which have been dug in the wild and replanted in order to be called cultivated." (Frontier Co-op 2000)
It is reportedly cultivated somewhere by tissue culture for ornamental uses (Tim Smith pers. comm.). Small scale cultivation for the horticulture trade is reported from Manitoba, but this involves gathering plants from the wild and transplanting them in nurseries. Techniques for propagating this species from seeds involve germinating them on agar and then transplanting them to soil, but these have not been perfected yet (Elizabeth Punter pers. comm.).
Because the roots of this species are being sold in the medicinal herb trade [and cultivation is perceived to be very difficult] it is certainly being collected from somewhere (Mike Homoya pers. comm.).
Like other orchid species, some populations have been reduced over the years by collecting for gardens (Weber and Wittmann 1996).
In Kentucky, Deborah White (pers. comm.) has received anecdotal information that all lady's slippers are being collected, and has received a call from a collector inquiring about federal regulations who claimed to have a large box full of roots. Ladies slippers have also been collected for gardens, but the transplants commonly fail (Deborah White pers. comm.).
This species is protected in Georgia as a Special Concern Plant, a category that is used for commercially exploited species that are infrequent in the state and often dug for horticultural or medicinal purposes (Georgia Natural Heritage Program). The situation in Georgia is described as follows: "Permits are required to dig, sell or transport [this species]. There is little enforcement carried out with regard to protected plants. Yellow ladyslippers are sold by half a dozen individuals who propagate the species by rhizome division mostly from plants on their own lands. There are some illegitimate nurseries still obtaining plants dug from the wild without permit or landowner permission. The yellow ladyslippers when sold by permit are required to have transport tags, a copy of which is filed with the Georgia Natural Heritage Program. During 1993 through 1999, records indicate that as few as zero individuals to as many as 43 individuals per year were sold by permit (as garden plants) in Georgia. There is no estimate on numbers taken without permit, nor do we have any misdemeanors filed against individuals for removing yellow ladyslippers within the past few years." (Tom Patrick pers. comm.)
Plants are probably collected in the southern part of the range of the species in Manitoba (Elizabeth Punter pers. comm.).
An individual knowledgable about the medicinal herb trade states that Cypripedium is insignificant in the market currently and estimates trade on the order of ten pounds of dry root per year (McGuffin pers. comm.). It may be that horticultural collection is a much greater threat than medicinal usage, but this requires further research.
Any serious efforts to collect this plant for the plant trade could have negative impacts on this species in Indiana, where it is not common (Mike Homoya pers. comm.). In Missouri, wild-collection for personal gardens threatens populations (Tim Smith pers. comm.).
All Cypripedium species are listed by the United Plant Savers At Risk Forum on their "At Risk" list. This list consists of "herbs which are broadly used in commerce and which, due to over-harvest, loss of habitat, or by the nature of their innate rareness or sensitivity are either at risk or have significantly declined in numbers within their current range" (United Plant Savers 2000).
Other than threats from plant collection and habitat loss, like many orchids, Cypripedium parviflorum var. pubescens may be relatively intolerant of degraded natural habitat (Swink and Wilhelm 1994), and to the extent that this is so, it is relegated to a decreasing portion of the natural landscape, which is threatened by pollution, changes in hydrology, resource harvesting, over-abundance of certain animals (such as deer), alien species invasion, and loss of landscape connectivity.
Other than collection, the following threats are reported from across the plant's range. Illinois: competitive exclusion by exotic species such as bush honeysuckle and garlic mustard (Bill McClain pers. comm.); Wyoming: grazing by livestock in the Bighorn Range, vulnerability to trampling by off-road vehicles and hikers (Walt Fertig pers. comm.); Idaho: weed invasion and right-of-way maintenance (Michael Mancuso pers. comm.); Mississippi: widespread land conversion, such as land clearing and the establishment of pine plantations (Ronald Wieland pers. comm.); New Mexico: individuals in one occurrence found with tops clipped off, not clear if due to grazing or collection (Sara Gottlieb pers. comm.); Georgia: rooting by wild pigs (Tom Patrick pers. comm.); Manitoba: road maintenance (herbiciding, mowing, ditch cleaning, removal of woody vegetation), forestry activities, agricultural activities (haying, grazing, tillage), and picking and digging of plants (Elizabeth Punter pers. comm.).