Chestnut Herbal School

Pink Lady's Slipper (Cypripedium acaule)

Written and Photographed by Juliet Blankespoor

Pink Lady's Slipper (Cypripedium acaule, Orchidaceae

Pink Lady’s Slipper (Cypripedium acaule, Orchidaceae)>

Lady’s slipper orchids have a commanding presence—their  inflated blooms are captivating to the point of heady swooning and inspiring colorful prose. The etymological root of the word orchid comes from the Greek orchis, meaning testicle. Certain species of orchid bear roots, which resemble paired testes. In pink lady’s slipper, it is the flower, and not the root, that is reminiscent of naughty bits. Orchids typically have three petals, with one of the flower’s petals forming a pouch-like structure, aptly named the labellum. The Latin root of labellum, is little lip, or labia. In pink lady’s slipper the labellum is inflated and heavily veined. The other two petals are pink and narrow, twisting, and extending out to the side of the flower, like a dancer’s arms in mid-twirl.

The enticing pink petals, along with the flower’s wafting fragrance, attract large bumblebees, who clumsily pry their way into the inner chambers of the labellum through the slit down the front. Once inside, the bees quickly realize they have been duped, as there is no nectar to be found. The bees are unable to retreat via the labellum due to the petal’s crafty design, so they look elsewhere for an escape from the pink luminescent chamber.

Close-up of a pink lady's slipper flower's labellum

Close-up of a pink lady’s slipper flower’s labellum

Let’s pause this sordid pollination tale for a moment, and perhaps project a bit onto the bee’s reality (never miss an opportunity to interpret life through an insect’s perspective). Do the trapped insects take a moment to reflect? Perhaps some bees, being of a naturally philosophical persuasion, might feel something like this: “Well, I took a wrong turn, but the color and the light in this silent cloister is so soothing and peaceful, perchance a nap is in order.” Or maybe the high-strung bee, traumatized by past encounters with nectarless flowers, begins to feel claustrophobic, maybe even a little sheepish, and becomes disoriented in their desperation to find freedom. Five of the panicked bee’s legs become ensnared in the labellum and the bee perishes alone.

But wait, let’s not let our daydream end in slow death sadness—our lady’s slipper is no insectivore; it eats dirt, not hapless bees! The totally buzzed out bee takes a deep breath and looks around. Light, up above! Freedom calls, and our bee gingerly pulls their legs free, one at a time, and flies upward and onward. They bang their head against something as they makes their exit, but eventually they wriggle free and go on to find a blueberry bush sporting ample flowers. All of which bear nectar, and are straightforward with their simple single opening.

When the bee exits the flower, they bump their head against the reproductive parts of the orchid, which are joined into a central bisexual reproductive organ, named the column. As the bee brushes against the lady’s slipper private parts, they pick up a mass of pollen. Now, most flowers produce thousands of pollen grains, all tiny separate structures, which our eyes perceive as gold dust. There’s enough to go around for all the pollinators, or for the breeze to pick up and transport to other flowers. But orchids have a different strategy—they put all their eggs into one basket, so to speak. All of their pollen grains are massed with waxy glue into one large pollen glob, which is called a pollinium. It’s a one shot deal. Which is perfect for a flower that doesn’t actually deliver. How many times will a single bee be duped? Eventually, the bee will wise up and realize those beautiful large lips are lying.

he narrow slit in the front of the labellum where pollinators enter, but do leave from

The narrow slit in the front of the labellum where pollinators enter, but do leave from

There is a reason that most flowers reward pollinators with nectar and/or pollen—it keeps them coming back. Only about 5% of lady’s slipper flowers are pollinated in a given year. Douglas Gill, of the University of Maryland, conducted a study on a population of pink lady’s slipper. He found that when the trees growing above the lady’s slipper were destroyed by gypsy moths, the orchids flourished. Flowering increased six-fold and the average successful pollination rate increased from 2.6% to 20.7%. Gill theorized that lady’s slipper increased visitation by bumblebees was due to the greater sunshine and openness and also proximity to heath family members, such as blueberry. He goes on to surmise that fire plays a role in the success of lady’s slipper pollination by periodically opening up the forest floor to more sunshine, and thus more pollinators. Fire suppression may be yet another stressor for this rare charismatic orchid.

Let’s return to our bee, who is presently satiated with blueberry flower nectar and resting on a cushiony clump of moss warmed by the dappled soft sunlight of the late afternoon. As they doze off into bee dreamland, they spy another lady’s slipper, and shudders with the recent memory of their temporary entrapment. But there’s a part of them, the one who is always searching for the fabled fountain of nectar, who whispers in their own ear, “That flower is so large, so succulent, surely there’s a treasure of nectar, a golden pool of sugar at the base of the flower.” Maybe the bee imagines slipping their mouthpart into a deep well of sweetness and drinking until they are so full they are unable fly home. The bee knows they shouldn’t, danger lurks, but they must.

Compelled, they enters the second lady’s slipper, more tentatively this time, and their heart drops when they behold the dry inner chamber. This time she will not allow herself to be flustered. She heads straight up towards the exit, and oeuff, there’s that danged thing they banged their head on last time. As the bee slips out the rim of the flower, the pollinium slips off their back, and lands squarely on the stigma of the flower.  Mission accomplished: pollen from our first lady’s slipper flower was delivered directly to the stigma of our second flower. The bee never looks back.

Now pollination takes place, then fertilization, and finally, thousands of minute orchid seeds are produced in a brown hard pod. The tiny seeds are so small that they can take a ride on the wind, but their size comes with a price. Most seeds have just enough reserves to see them through until they are able to photosynthesize and make their own way in this wide wild world. Not orchid seeds. Smaller than a grain of salt, in the beginning they are at the mercy of fungi for everything. When the seed meets up with a tentative strand of mycelium (fungal body) they join in inter-species rapture (alright, perhaps more conjecture and anthropomorphizing, but it’s so fun to pretend!). The fungi helps the seed to germinate, and nurtures it along, as they begin a lifelong love affair, or symbiosis.

It can take three years from germination until the lady’s slipper seedling even makes its first green appearance above ground. And then another three to five years before its big enough to flower. Once a lady’s slipper is established, it lives for an average of two to three decades, flowering every few years or so. Some authors claim that the plants can live for over a century, and possess the ability to remain subterranean for years, even up to a decade, when conditions are adverse. Lady’s slipper may engage in some serious floral shenanigans, but it does eventually repay its debt to its early fungal benefactor by sharing some of the sugars it produces through photosynthesis.

Cypripedium acaule, Orchidaceae

Cypripedium acaule, Orchidaceae

One might imagine, with this slow growing lifestyle and deceitful germination strategy, that lady’s slippers are not that abundant. And one would be right. Lady’s slipper root was once a popular medicine, overharvested for its use as a nervine, relaxant and aphrodisiac. By the time I came of herbal age in the late eighties, most herbalists had already stopped using lady’s slipper due to its scarcity. I imagine the harvesting of lady’s slipper for medicine to be as shameful as killing a rhinoceros for its medicinal horn, or a black bear for its gall bladder. Maybe even as dastardly as slaying a unicorn to use its horn in flying medicine.

Although lady’s slipper is no longer harvested for medicine, it faces other threats in the form of habitat loss and poaching. The plants are often dug up and either sold or replanted. Most plants do not take well to transplanting, perishing or languishing, as the fungal/root connection is disturbed. Please never pick lady’s slipper for medicine, and never attempt to dig it up and transplant it.

Pink lady’s slipper’s scientific name is Cypripedium acaule; the species name means stemless, which is somewhat confusing as the flower actually has a stem. But the flower stem is not technically a stem—it’s a flower stalk, which botanists call a scape. Cypripedium acaule can easily be differentiated from other lady slipper species because its flower stem has no leaves. Pink lady’s slipper grows in dry or wet acidic woods, under conifers such as pine and hemlock, or in mixed hardwoods. In the southern Appalachians, I see it growing under sourwood, white pine and tupelo trees. Its range extends from Newfoundland, west to Alberta, down into northern Alabama and eastern Georgia.

I spend a lot of time romping through the woods, and pink lady’s slipper is as uncommon as ginseng in southern forests. Some years there are few flowers; this year the elements have been kind and many lady’s slippers are flowering. These photos are from a patch I have been visiting for a decade. The plants are close to a road and a well-traveled trail, yet people have let them be. I have seen no sign of harvesting or digging. The only people I see near the patch are wildflower enthusiasts making their annual pilgrimage to pay homage to this rare beauty. It gives me hope for the humans, and hope for the future of lady’s slipper.

Meet the Green Mastermind Behind Blog Castanea:

Juliet Blankespoor

JULIET BLANKESPOOR is the founder, primary instructor, and Creative Director of the Chestnut School of Herbal Medicine, an online school serving thousands of students from around the globe. She's a professional plant-human matchmaker and bonafide plant geek, with a degree in botany and over 30 years of experience teaching and writing about herbalism, medicine making, and organic herb cultivation. Juliet’s lifelong captivation with medicinal weeds and herb gardening has birthed many botanical enterprises over the decades, including an herbal nursery and a farm-to-apothecary herbal products business. 

These days, she channels her botanical obsession through her writing and photography in her online programs, on her personal blog Castanea, and in her new book, The Healing Garden: Cultivating and Handcrafting Herbal Remedies. Juliet and her family reside in a home overrun with houseplants and books in Asheville, North Carolina.

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38 thoughts on “Pink Lady’s Slipper (Cypripedium acaule)

  1. Sandra Thorkelson says:

    Good morning!
    I read your nice entry and it was really entertaining. I’d like to offer a different suggestion to leaving these lovely plants alone. I’m Ojibwe and our teachings tell us that we are an intrinsic part of Mother and our role is to help plant life in return for the gifts they give us. It’s our job (just like bees, bears, and everything else) to help spread seeds. So if you are fortunate enough to find a lady slipper seed pods, feel free to spread it somewhere else close where it might like but there aren’t any. You might not get to see them, or enjoy them, but your children might. I do this with many plants, especially as development encroaches on new land. Humans are supposed to be caretakers, and recently we haven’t been doing a great job. These plants can’t get up and run, but maybe we can help them in that regard.


  2. I live in Oregon but love reading the plant stories from “your neck of the woods.” I signed up for your class and am eager for it to start!

  3. Forest Grace says:

    What an amazing profile on this plant. Thank you SO much, Julia. Riveting writing
    and so much wonderful information.

  4. You bring up such wonderful memories of going for nature walks with one or the other of my parents. My father especially would make sure we saw the one on our property on the years it flowered. Dad passed a couple years ago. Thank you for the great memory and wonderful article too!

  5. I am curious if (or how long) Katrina & Jan’s transplanted slippers lived. The mycelium the pink slipper requires to live can be quite large. Here in the Appalachians of NC (where we revere Cyp. acule), in horticulture we are taught that breaking one mycelium tube can result in eventual death of the slipper. We have cultivated Cyp. acule in our micropropagation lab at Mayland Comm. College in Spruce Pine, NC. In the lab we have been able to get around needing the mycelium for germination and have been able to get them to the point of moving to the greenhouse and then outdoors. Hopefully to free them from the need for the mycelium. The consensus here is that Cyp. acule (the only slipper that requires mycelium) may live for 2-3 years when transplanted from the wild, but not have the long life expected. I have raised the question of possibly inoculating the ground with the mycelium at the transplant spot, maybe it would at least help the (hopefully) seed produced before it dies.

  6. Lindsay Perry says:

    Um, Juliet this is kinda steamy! Maybe for your second career you can market yourself as a botanic-erotica novelist.

  7. Hi!
    The other day, while in the Gothenburg Botanical Gardens, my husband and I came across some of these amazing looking flowers. Then we saw a bumble bee fall in! We were halfway through wondering if we should rescue the poor thing, when a quick google search brought us your blog, and the amazing explanation for what we’d just seen. Sure enough, the brave little lady squished her way through the top exit from the flower and made it out alive (though slightly sticky). It was truly an amazing experience and one made far greater by reading about what we had witnessed. I’m writing about it on my blog today, and will mention this post.
    Thanks again,

  8. We have a patch of slippers which we call Mocassin orchids up here in central Ontario Canada at a small glade by our lake. They’ve suddenly shown signs of proliferating. From a single flower in 2002 we are now up to 6. I found by getting low to the ground of one and looking outward in the distance I was able to identify severl similar duo-leaves growing that had yet to produce a flower, but sure enough they were indeed slippers as well. 14 years – gives you an idea of how slowly they spread. We give them a very wide and cautious birth and photogragh their growth annually. I can’t imagine how I’d feel if they went missing! I’d swear the photos you shared were mine. Simply lovely. This year was the first I actually put my face close enough to smell their fragrance – quite soft. And it’s a rarity to see a bee or bumbler get trapped inside, the flower bouncing around like it’s dancing – quite a pink testicle-spectacle! Sorry – just had to say that. 🙂 Appreciate your humor and time spent writing. Regards – Steve

      • Thanks, Juliet! They all were pollinated. Woohoo! I’ve been watching each day as they shrivel from their magnificence and their seedpods fatten. May they have a gazillion babies that live long lives and spread! 🙂

  9. Terry Bottoni says:

    Thank you for this site. I discovered one in my New Jersey pine lands backyard today. I could not find it on the internet until I searched pink testicle wild flower and here I am! Great info above again thanks.

  10. Katrina Yurenka says:

    First, this is a fabulous article, answering all of my questions in an unbelievably wonderful way. I am blessed by having a few lady slippers on my property. There is an area that I walk by frequently that had an abundance of lady slippers until the land was destroyed and made into a parking lot for dumpsters! I did go and rescue as many lady slippers as I could before the ground was paved over……

  11. I loved your article. Thank you. Here’s my dilemma. We live abutting the Town Forest, which also is attached to a very busy soccer field for youths and persons of all ages.
    The beautiful pink lady slippers I saw are blooming right by the foot path to the field. I fear they will get stomped on by some unknowing child or person. There are up to 200 cars in the parking lot at times. Should I transplant them (only those in harms way) and place them in the woods closer to our home? They would be much safer there and it is their habitat. I would use the same transplanting technique as suggested by another commenter. Or should I let them be and let nature take its course? Thank you for your help!

    • I would leave them – others could be enjoying them too! If you really think they are in foot traffics harm, you could make a little sign or fence around them, maybe combined with the town’s efforts!

  12. Oh by the way, when we moved them, I took a spade and inserted it in the ground straight down about 12 inches from the plant base. I did that completely around the flower. Then I repeated it going deeper each time. Then we loosened the dirt well below the roots of the flower before removing the 2 ft wide section. I did not want the roots touched by anything. I did not want the flower to even realize it had been moved. So we worked carefully and slowly. They were set in a very similar place closer to my home. They can be moved, but it’s not recommended. And if you try it please do so carefully as they are endangered and protected by law, at least here in the East Tennessee Appalachian mountains.

  13. My husband has a few acres of undeveloped woods. I love to go on hikes through the woods. I have found nearly 50 of these beautiful flowers. We moved about a dozen of these closer to the house but still in the woods. I take photos every year when they bloom. Looks like God spent a lot of time on this one. It is so unique! I loved reading this article. I learned a lot more about them. Thanks for this page/article.

  14. Oh My..what a lovely read on my favorite woods find! You kept me captivated and engaged as I was truly connected to your beautiful writing. Gratitude!!

  15. Juliet–thank you for this wonderful blog post! It was just the medicine I needed this morning! I learned so much that I never knew before about one of my favorite plant teachers. I am fascinated by mycelial connections and the ingenious pollination of Pink Lady’s Slipper.

    Have you worked much with the flower essence? I have found it to be very useful for reconnecting with the pure sensation and ease of embodiment and letting go of judgement/fear/trauma surrounding negative beliefs around one’s physicality and sexuality. Do you think it harms the plant to make an essence by weighting the blossom delicately down into water without plucking it? Would love to know your thoughts.

    Thank you for sharing!

    Sophia Rose

    • Sophia,
      thank you for sharing about the uses of the flower essence, I don’t really use flower essences but i love hearing about them 🙂
      I don’t have any experience with the careful flower essence method you described – it seems like if it spring back up after, it should be fine, maybe a really short touching with the water -like a baptism?
      thanks for reading and sharing!

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