Pink Lady's Slipper

Cypripedium acaule

UW-Madison, Department of Botany

Pink Lady's Slipper is an interesting wildflower in the Orchid Family. They are endangered in some areas because they take a long time to grow, and because people collect them.

This plant has only two leaves. They are green and branch out from the center of the plant. A single flower stalk also grows from the center.

The deep pink flower, which many people say looks like a slipper, grows about three inches long. Unlike most flowers you see, this flower is closed tightly except for a small opening in the front.

Pink Lady's Slippers grow in shady forests under pine trees, oaks, Red Maple, and Sweetgum. Some other plants that grow alongside them include Greenbrier and Sassafras.

Pink Lady's Slipper is a food source for several insects and White-tailed Deer.

Michael W. Thompson

Copyright, Native Sons Nursery

In order to spread and grow new plants, Pink Lady's Slipper needs help from other organisms. First, when a new seed is ready to grow, it must have a fungus help it. The fungus has not been identified by scientists yet, but we know it is in the Rhizoctonia Genus. The lady's slipper seed does not have a food supply inside it, like most seeds do. It needs the threads of the fungus to break open the seed and attach themselves to it. The fungus will pass on food and nutrients to the Pink Lady's Slipper seed.

The seed will grow very slowly into a new plant. Without the fungus helping it, the plant could not grow. The plant will return the favor to the fungus when it is older. The fungus can soak up nutrients from the lady's slipper that it could not get by itself. Pink Lady's Slippers can live to be twenty years old or more.

This wildflower also needs help from bees. Its closed flower means that only a strong insect, like a bumble bee can push its way inside. The flower smells sweet, so the bee is tricked into thinking it holds nectar. When the bee gets inside it not only finds no nectar, but it realizes it is trapped. It cannot get back out the way it got in. The bumble bee explores and find a new way to squeeze out of the flower. To do so, it must push past a part of the flower called a stamen. The bee gets out, but it also gets covered with pollen that was on the stamen.

If the bumble bee gets tricked again by another Pink Lady's Slipper, it will deliver pollen from the first flower, and get covered with pollen again by the new flower. The bee may do this several times before it figures out to avoid Pink Lady's Slipper. The bumble bee gets nothing out of the relationship. Without the bee's help, the plant could not make new seeds.

Relationships in Nature:

Animals Using as Food Source

Animals Using as Shelter

Associations With Other Plants


White-tailed Deer

Eastern Forest Snail

Eastern White Pine

Golden Northern Bumble Bee Po

Eastern Forest Snail

Leopard Slug


Rhizoctonia Fungus Mu

Six-spotted Tiger Beetle

Black Oak

Common Black Ground Beetle

Virginia Pine

Field Cricket

Loblolly Pine

Garden Centipede

White Oak

Eastern Worm Snake



Red Maple

Relationship to Humans:

Most people enjoy seeing these beautiful flowers. Unfortunately, it also means a lot of people try to collect them from the wild to have as their own. Since this flower takes many years to grow, if too many people take them, they cannot continue to survive in the wild. Also, since Pink Lady's Slippers cannot grow without the Rhizoctonia fungus, the plants people collect usually die anyway. Many people are trying to protect Pink Lady's Slippers, and in most places it is now illegal to take them out of their habitat.


Cypripedium acaule


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