Pink Lady’s Slippers: Strange and Beautiful

by Linda Martinson

May 2016 

Every April I hike over to check out the glade with mossy sink holes and towering pine trees to see if the pink lady’s slippers (also called pink moccasin flowers) are blooming yet. If it’s too early, there’s no sign of them. But then, toward the end of the month and into May, almost overnight it seems, there are several plants each with two leaves and a flower stem standing in quiet majesty with their stunning pink blossoms. Lady’s slippers have long-lasting blooms and they mature slowly, taking many years to go from seed to a mature plant. Once mature, each plant can live up to 20 years. So a glade of lady’s slippers is a gathering of elders.

A glade of lady’s slippers is a gathering of elders.

                                        Photo credit: Linda Martinson

Pink lady’s slippers belong to the orchid (Orchidaceae) family — a very large, diverse, and widespread family of perennial herbs usually with showy blossoms. Orchids have one fertile stamen and three-petalled flowers, which can vary greatly in shape, size, and color — for example, they can be small, pale specks or a large bulbous mass or look like an elfin face. Like many herbs, the orchid plant family has some medicinal and food uses, and an extraction from the roots of our native pink lady’s slipper was used to treat nervousness, tooth pain, and muscle spasms by both native Americans and early settlers. The pink lady’s slippers of the Southern Appalachians (Cypripedium acaule) grow mostly in mixed hardwood/coniferous forests with mossy rocky slopes or in deep humus and acidic but well-drained soil under birch and other deciduous trees.

The orchid family is considered to be the most numerous of flowering plants, with over 25,000 named species throughout the world, and the most highly evolved. To put it in perspective, there are twice as many orchid species as there are total bird species and about four times the number of mammal species, and they account for up to 12% of all seed plants. Orchids have adapted to every environment on earth except the very coldest, and have been mutated, crossbred, and cloned into over 100,000 hybrids and cultivars of orchids with new ones being developed all the time. There are thousands of orchid collectors, clubs, and shows all over the world, and thousands of people who are obsessed with orchids. In a New Yorker article entitled “Orchid Fever”, the author wrote, “Generally speaking, orchids seem to drive people crazy.” 

…there are twice as many orchid species as there are total bird species and about four times the number of mammal species…

Orchids have certainly had time to evolve, because they have existed for at least for 100 million years, which means they were part of the world of dinosaurs. To achieve their elegant evolution, botanical complexity, and mutability, most native orchids have become niche plants with highly specialized pollination systems, often limited to a specific habitat and often quite rare. For example, most species of wild orchid depend on just one insect species for pollination, which partially accounts for both their amazing diversity (since insects are the most diverse land animals) and for their frequent dependence on the limited and specific habitat of just one insect species. 

Pink lady’s slippers are perfectly shaped to use bumblebees for pollination: the flower’s hollow slipper or moccasin has a convenient lip for bees attracted to its bright color and sweet scent to land upon and slip inside for the flower’s nectar, but then it is trapped and has to climb up through the tight hood of the flower first passing against the female stigma and then picking up pollen from the male pollen sacs and hopefully carrying it to another lady’s slipper to fertilize it. However, lady’s slipper orchids, like most orchids, don’t have a mutually beneficial relationship with their pollinating insect — i.e., they don’t provide nectar for their visiting bees. So, eventually only the rare bumblebee visits the lady’s slippers, which is a partial explanation for why the flowers bloom so long and live so long — they are quietly waiting for the lone bee to come by so they can reproduce. 

Photo credit: Jim Poling

Fortunately, although not many seed pods are produced, each one contains a huge number of tiny seeds which disperse easily. However, there is another critical step in the pollination process of most orchids including lady’s slippers. In general, orchid seeds do not have a food supply inside them, so pink lady’s slippers, like most orchids, partner with a fungus in the soil (their fungus is from the Rhizoctonia genus), so that their seeds can germinate. When a seed falls near them, the threads of the fungus surround the seed, break it open, and pass nutrients to the seed so that it can germinate. The relationship between the lady’s slipper and the fungus is somewhat symbiotic because, as the seed grows into a plant that is producing most of its own nutrients, the fungus will begin extracting some of its nutrients from the orchid’s roots. It is apparently the orchid, however, that benefits more from its partnership with a fungus. 

This relationship with a fungus is typical of almost all orchid species, so it is almost impossible to transplant them successfully. For this reason, and because they are usually fairly rare, take so long to mature, and are restricted in location, native orchids should never be picked or dug up.  There are, however, some cultivars of lady’s slippers and other more hardy species of native orchids that are offered for sale, but do make sure that the company selling them is reputable.

native orchids should never be picked or dug up.

We are fortunate to have over three dozen species of native terrestrial orchids in Western North Carolina, with some common and easily found species blooming from spring through the fall. For example, both pink and yellow lady’s slippers bloom in the spring with showy orchis and putty root; small green woodland orchids, cranefly orchids, and rattlesnake plantains bloom in the summer; and yellow fringed orchids bloom in the fall. These orchids, like so much of the wonderfully diverse flora and fauna of the Blue Ridge, are all deeply dependent on maintaining undisturbed and undeveloped habitat.

The most commonly seen native orchids in the Blue Ridge and Southern Appalachians are: Pink lady’s slipper, yellow lady’s slipper, showy orchis, and rattlesnake plantain (pictured below). I know of eight orchids that have been identified at Richland Ridge to date: the four pictured below, green woodland orchid, orange fringed orchid, Cleistes rosebud orchid, and yellow crested orchid, and it is likely that we have putty root and cranefly orchids here, too.

Photo credit: USFS

References:   Frick-Ruppert, Jennifer. Mountain Nature. UNC-Chapel Hill, 2010.

Orlean, Susan. “Orchid Fever.” The New Yorker. January 23, 1995.