Orchid of the Month
Cypripedium acaule

Cypripedium acaule
​May 18, 2018

May 26, 2018

The Cypripedium acaule is a hardy orchid that is native to the eastern United States from southern Georgia into Canada. It’s hardy in USDA Hardiness Zones 2 – 8; and, its common name is the Pink Lady Slipper. It thrives in a shaded, well-drained environment and is often found in pine forests. There are three unique characteristics about this hardy orchid:

• The labellum of this orchid has a slit that runs down the center of the pouch rather than an opening at the top of the pouch.
• Unlike most hardy orchids, Cyp acaule does not have a close myco-heterotrophic relationship with soil fungus. As a matter of fact, it doesn’t like having fungus in the soil around it.
• It only grows in soils that have a pH below 5. At this pH, fungus is not present in the soil. This is one reason it often found in pine forests.

In April or early May, two pleated leaves appear from the soil. A single bud spike will emerge from between the leaves and produce one bloom. I found this Cyp acaule during walks at the O. D. von Engeln Preserve at Malloryville, NY.