Lady’s-slipper orchids are a joy to behold!
There are approximately 45 species of lady’s-slipper orchids (genus Cypripedium) in the world. They are found nearly throughout the Northern Hemisphere, but especially in temperate Eurasia and North America.
Of the approximately 15 taxa in North America, the white lady’s-slipper orchid (Cypripedium candidum) is one of the very smallest. The whole plant is often only 15–25 cm tall and the tiny lip or namesake slipper part of the flower is only 17 to 27 mm long. For comparison, the slippers of some of its eastern North American relatives (large yellow lady’s-slipper orchid, Cypripedium parviflorum var. pubescens and showy lady’s-slipper orchid, Cypripedium reginae) are usually more than twice as long.
The white lady’s-slipper orchid can be very difficult to find when it is not in flower and may lay hidden under overhanging vegetation. Fortunately, it usually grows in small clusters of many flowering stems, sometimes upward of 50. Look for the white lady’s slipper orchid in alkaline wetlands, usually fens, wet-mesic prairies, or around the edges of sedge meadows. Be prepared for wet knees as your search may require crawling to find and inspect the flowers up close! Flowering usually occurs in mid- to late-May with extreme flowering records as early as late April and as late as mid-June.
Although NatureServe designates the white lady’s-slipper orchid as globally secure (G4), this species is currently rare to uncommon throughout its range. It has been recorded in 18 eastern U.S. states, mostly in the northeast and northcentral parts of the country, with isolated records from Alabama.
The white lady’s-slipper orchid is Presumed Extinct (SX) in Pennsylvania, Critically Imperiled (S1) in South Dakota, Nebraska, Missouri, Kentucky, Alabama, Virginia, New York, New Jersey, and Maryland, Imperiled (S2) in North Dakota, Wisconsin, Illinois, Michigan, and Ohio, and Vulnerable (S3) in Minnesota, Iowa, and Indiana (NatureServe 2020).
Unfortunately, this once widespread and at least occasionally encountered species has suffered a drastic decline in population numbers. The primary reasons are habitat loss, invasive species, woody encroachment, and outright poaching.
In Illinois, the white lady’s-slipper orchid has a similar story. It was once widespread and at least occasionally encountered.
Records stored in herbaria throughout Illinois and across the country document this species from 25 counties across the north half of the state. Unfortunately, many of these populations were lost very early as Illinois was settled. Widespread conversion of land for agriculture has all but extirpated the species from downstate Illinois. Mohlenbrock (1970) stated “this species, along with the yellow lady’s-slipper and the showy lady’s-slipper, were not infrequent in the state before 1900. Indiscriminate collecting, however, has made all of these species rare in Illinois to the point of extinction.” Additional population losses accumulated over time and, by 1981 when the inaugural Illinois rare plant list was published, this species was listed as endangered within the state.
Fortunately, this is when the story started to change for this tiny, endangered plant.
Many populations have been discovered and protected in numerous state nature preserves, county forest preserves, and on private land since 1981. People care and began to protect and steward our remnant natural communities. Natural community restoration and habitat management started to become a common, widespread practice and the results were being seen on the ground.
By 1999, things were starting to improve for the white lady’s-slipper orchid and the species was downlisted from endangered to threatened.
Staff and volunteers with the Chicago Botanic Garden’s Plants of Concern Program (POC) have monitored the white lady’s slipper orchid for several years (to date, more than 50 populations). For this rare species, habitat management in the form of prescribed burning, invasive species management, and removal of encroaching woody species resulted in population increases at many sites.
The white lady’s-slipper orchid was officially delisted in Illinois in 2015.
Of course, the story doesn’t end here. Continued vigilance and care are needed. Natural remnants must always be protected and cared for.
NEVER remove any native plants from remnant sites unless the population is threatened with certain destruction. Naturally occurring remnant plant communities are invaluable and represent years of crucial interaction and relationships among the environment and its inhabitants (plants, animals, fungi). For many species, these conditions cannot be easily created.
Cultivation of lady’s-slipper orchids require very specific conditions and significant knowledge and most efforts to cultivate lady’s-slipper orchids in a home garden or even in a restoration area will result in death of the plants. Please, don’t do that.
Also, only purchase native plants, especially rare species, from reputable dealers that are growing and actively propagating the species.
In Illinois, most downstate white lady's-slipper orchid populations have been lost but a few remain intact. Let’s expand on the work that has occurred in northeast Illinois and do what we can to save this species throughout Illinois and throughout its range.
Herkert, J.R. and J.E. Ebinger, editors. 2002. Endangered and Threatened Species of Illinois: Status and Distribution, Volume 1 – Plants. Illinois Endangered Species Protection Board, Springfield, Illinois. 161 pp.
Mohlenbrock, R.H. 1970. The Illustrated Flora of Illinois, Flowering Plants, Lilies to Orchids. Southern Illinois University Press, Carbondale and Edwardsville, Illinois. 288 pp.
NatureServe. 2020. NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available at https://explorer.natureserve.org/. (Accessed: June 5, 2020).
Plants of Concern. 2020. Plants of Concern, a project of the Chicago Botanic Garden. Plants of Concern, Chicago, Illinois. Available at https://plantsofconcern.org/our-policies. (Accessed June 5, 2020).
Sheviak, C.J. 2002. In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 19+vols. New York and Oxford. Vol. 26.