Cypripedium calceolus and its close cousin C. reginae are cold hardy ground orchids that are as easy to grow as most garden perennials. Both species are commonly known as Lady Slipper or Moccasin Flower because of their shoe-shaped blooms.
Unlike its heat-loving sibling the Paphiopedilum Lady's Slipper which hails from the tropics, Cypripedium calceolus is native to North America and northern Europe and needs a cold winter rest in order to bloom well each summer.
This interesting and elegant wild orchid makes the cool woods from Maine to the mountains of California its home in the U.S. In early June their flowers illuminate the forest floor like golden drops of sunlight.
The shoe-like portion of the bloom is actually its lip and it has a job to do.
No, this functional flower does not exist to provide the fairy folk with footwear; it serves as a bug trap.
Once an unsuspecting insect has ventured into the pouch, it will deposit any pollen on its body onto the Moccasin Flower's stigma. On its way out (Cypripedium orchids do not kill their victims like pitcher plants, they only use them briefly) the beleaguered bug picks up more pollen from the Moccasin Flower which it then spreads to other orchids after it makes its escape.
C. reginae grows to 3 feet tall (Cypripedium calceolus tops out at 2 feet) and sports flowers with a pink pouch and white petals and sepals which appear a week or 2 later in the growing season than those of C. calceolus.
Both species adorn their stems with lime green, wavy, ridged foliage which looks like little hosta leaves and melts away in summer's heat.
Cypripedium reginae is commonly called Showy or Queen's Lady Slipper.
These ground orchids grow best in constantly moist, humus rich soil which is neutral to slightly acidic. The best exposure is part or high shade like that found beneath deciduous trees.
Plant nursery grown plants by either sinking the pot or carefully removing the orchid from the container and placing it into the soil.
Sinking the pot offers the following advantages:
When potted plants become too large, carefully divide the root mass into 2 portions--more divisions will cause too much root disturbance--and repot or replant them.
Mocassin Flowers and Showy Lady Slipper look most fetching when planted amongst rocks or with woodland plants like ferns in zones 3-6.
Watch out for slugs and snails as these pests are attracted to Cypripedium leaves.
Water the plants only enough to keep the soil from becoming dry and do not feed them. If there is enough humus in the soil, they will not need it.
If you don't believe your soil is adequate, amend it with composted leaves before you set the plants in place.
Related Plant: Cypripedium acaule, the Pink Lady Slipper