They look like tiny, fancy dress slippers waiting for a fairy lady to don them for the ball. But lady's slipper orchids (Cypripendium spp.) are a far cry from the delicate ornamentals you might think. This genus includes some 50 species of terrestrial orchids, plants that ordinarily grow in the wild in a range of habitats from dry woodlands to marshes of the Americas, Europe and Asia. But that does not mean they are easy to grow in your backyard.
You can easily recognize lady's slipper orchids by the stunning colors and shapes of its blossoms; each has three petals, three sepals and a lower petal that looks like a pouch. However, spotting one might be more difficult; although the Cypripedium genus includes dozens of species of orchids, lady's slippers are rare both in the wild and in cultivation. Different species thrive in different habitats from arctic to subtropical, but most grow in cooler zones, like the showy lady's slipper (Cypripedium reginae) in U.S. Department of Agriculture plant hardiness zones 3 through 7.
Orchids have a reputation as high-maintenance hot-house prima donnas. Lady's slipper orchids are difficult to grow, but not for the standard reasons. These plants only survive in a very specific habitat that requires the presence of other plants. Some grow near certain species of evergreen trees, for example. They take up a specific soil fungus from the soil called mycorrhiza, which is only present in that particular habitat and results from a particular mix of vegetation. If a lady's slipper is removed from that habitat, it dies. Never dig these orchids from the woods or buy them from people who do.
Pink Lady's Slipper
Pink lady's slipper (Cypripedium acaule) is a woodland orchid that is nearing endangered status in the wild because of too-eager gardeners. Each flower has a bright pink pouch and paler pink petals, and the leaves are thin and up to 12 inches long. Expect to pay a pretty penny for a nursery specimen as it can take seven years for a plant to grow to flowering stage from a seed. Grow nursery-cultivated plants in moist, fertile soil that is acidic and well-draining. These shade-loving plants are very difficult to grow, but generally do best in USDA hardiness zones 3 through 8 and prefer leaf-mold mulching in winter.
Showy Lady's Slipper
This lady's slipper is the state flower of Minnesota and native to wetlands throughout the Midwest. Extremely rare in cultivation, the plant requires very wet soil, a partly shady location and humus-rich soil. In the wild, showy lady's slippers grow in clumps a yard high and hold their blossoms above on individual stalks. If you decide to take the plunge, remember that all lady's slipper orchids are so difficult to grow that Charles Darwin himself tried and failed.