Photo by Melody

PlantFiles: Species Orchid, Eastern Fairy Slipper, Bulbed Calypso
Calypso bulbosa

Family: Orchidaceae (or-kid-AY-see-ee) (Info)
Genus: Calypso (kal-IPS-oh) (Info)
Species: bulbosa (bul-BOH-suh) (Info)

Synonym:Cypripedium bulbosum
Synonym:Cytherea bulbosa

14 members have or want this plant for trade.

Alpines and Rock Gardens

under 6 in. (15 cm)

24-36 in. (60-90 cm)

USDA Zone 4a: to -34.4 C (-30 F)
USDA Zone 4b: to -31.6 C (-25 F)
USDA Zone 5a: to -28.8 C (-20 F)
USDA Zone 5b: to -26.1 C (-15 F)
USDA Zone 6a: to -23.3 C (-10 F)
USDA Zone 6b: to -20.5 C (-5 F)
USDA Zone 7a: to -17.7 C (0 F)
USDA Zone 7b: to -14.9 C (5 F)
USDA Zone 8a: to -12.2 C (10 F)
USDA Zone 8b: to -9.4 C (15 F)

Sun Exposure:
Partial to Full Shade

Handling plant may cause skin irritation or allergic reaction

Bloom Color:

Bloom Time:
Late Winter/Early Spring
Mid Spring
Blooms all year


Other details:
Average Water Needs; Water regularly; do not overwater

Soil pH requirements:
6.1 to 6.5 (mildly acidic)

Patent Information:

Propagation Methods:
By dividing rhizomes, tubers, corms or bulbs (including offsets)
From seed; germinate in vitro in gelatin, agar or other medium

Seed Collecting:
Unknown - Tell us

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5 positives
2 neutrals
No negatives

Gardeners' Notes:

Positive paulownia_lover On May 31, 2010, paulownia_lover from Beaverton, OR wrote:

The Calypso Orchid grows wild on Decatur Island in the San Juan Islands of Washington State. It's usually found in duff and moss a foot or two inside the edge of fir forest, often along dirt and gravel roads with unimproved ditches. The island's old-timers called them Lady Slippers, and the story goes that in the first half of the 20th century, the island's dentist would go out on his wife's birthday in March to pick her a large handful. The orchids are harder to find now. As the island's population has grown, the orchid's population has declined.

Positive buggycrazy On Aug 22, 2008, buggycrazy from Lebanon, OR (Zone 7b) wrote:

slugs, racoons and BIRDS devour these so they should be screened and slug baited all year. Extremely drought tolerant in the soil, should be kept barely moist if in a container. Also avoid fertilizers and fungicides as these may kill the symbiotic fungi that grows with it, if grown in containers a good topdressing of woods duff every year in the summer when dormant is recommended.

Neutral JerryMurray On Dec 18, 2004, JerryMurray from Belfair, WA wrote:

In my many travels as a forester through the Pacific Northwest I have encountered fairy slipper numerous times and in diverse habitats. Most populations I saw contained light purple to dark purple forms of the species. In 1980 I encountered an all-white individual growing in moss in a British Columbia, Canada, yellow cedar forest, and a friend found an albino population in northern California in 2001. One author shows a photograph of a yellow-flowered clump located in the Olympic National Forest in Washington state. Other locations I have seen Calypso include a fairly dry brushy area along the Kootenai River, Montana, just south of the dam; and the Blue Mountains of Washington, where the species grew directly in moist dense moss along a streamside dominated by a closed-canopy Picea englemannii forest - Cypripedium montanum grew not too far away on a slope in a ponderosa pine/pine grass environ. I found many populations of fairy slipper on Site III Douglas fir habitats at Seaquest Park near Castle Rock, Washington - these populations have been extirpated by human use (a day camp is built at the heart of the fairy slippers) and mole activity occurs that lifts the bulbs or causes them to be buried - no plants remained when I last checked. I also found a single small clump near my home in Belfair, Washington, growing in moss amongst salal on an old overgrown cat road (also Site III). In 1998 I encountered literally hundreds of Calypso orchids in a campground near Trout Lake, Washington, where they grew in moss-covered stony soil and on rotted logs under an open Douglas fir canopy. I have not visited the site since. The last Washington population I found is in Dungeness at the fish hatchery. A few indiviuduals were growing on a road cutbank hidden by grass and brambles in an old-growth DF forest. These were very light-colored lavender, one of which had an enormous leaf size of 8.3 cm. Cave Junction, Oregon, is the last location for Calypso that I am familiar with. Scattered individuals were found in a low flat area amidst deciduous shrubs and poderosa pine.

As sensitive as this plant is known to be, given the right germination conditions it is as adaptable as it is beautiful. I will be experimenting with germination in 2005 (any tips appreciated), since I have three Calypso bulbosa with budded stalks which are already up 1/4" as of December, 2004.

(All descriptions on my Calypso observances came from notes written in my trusty Hitchcock, Flora of the Pacific Northwest, 1976 edition.)


Positive GeorgesLess On Jun 9, 2004, GeorgesLess from Fort Smith
Canada wrote:

I live in Fort Smith, Northwest Territories X0E 0P0, Canada 6000'N, 11158' W
Calypso Orchid Calypso bulbosa grows here in the Boreal forest and I have been lucky enough to have taken some nice pictures of it.

In the specific place where I found it... there were seveal other groupings of the plant... all growing in the wild.

We are just on the edge of the Wood Buffalo National Park on the shore of the Slave River.

Wood Buffalo Park is a very specific almost micro climate area with many unique features... like the most northern nesting point of the White Pelican and the Whooping Crane.

Positive seb_number1 On Jun 7, 2003, seb_number1 wrote:

I'm french, And I grow C.bulbosa (origin: Canada) since 9 months. The plants (6 plants) seems to like spring potting, just when the plant has developed a single leaf, at this time, the roots are white and the corm is billowy.
I use a personal potting mix which is made of charcoal (1/10), fine quartz sand (2/10), pine bark and needle humus (4/10), and leaf humus (3/10).

All this elements must been mixed together, I prefer sterilize the mix (in microwave, maximun power during 15 min) because the fungus who lives on Calypso roots needs no more other concurrents fungus species.
Use the mix after 2 days !
It's my opinion, try an other way if you want...

The plants need full shade nevertheless a bright place.
A location under trees seems to be a good choice.
I water my plants with water pulverization on the top of the pot. The water must be only rain water or demineralized water ! Never use faucet water !

Be aware that slugs and snails love Calypso ! You must absolutly protect your plants because a single slug can eat many plants during an humid night !

Never use fertilizer or enriched substrate !
Don't forget that if you grow Calypso, you grow also his fungus (he is fragile!).

When you pot Calypso, you must put the corm at the top of the mix, or half covered with mix but no more, over this you must put a moss layer (1cm thickness, no more), hence the corm is situated between the mix and the moss.

The substrate must be humid in spring and sumer, when the leaf dry out, reduce water, keep the mix a little humid in winter, the fungus like this :)

I think that this comment on C.bulbosa is the most exact on the WeB, if you need more informations, email me at or

Positive dorr On Apr 7, 2003, dorr wrote:

I just located this splendid orchid in the Pacific Northwest; sea level; on an evergreen forest, floor. At the time the high temperature for the day was seasonably low ~43F (although we've had a very mild spring); windy with showers. The orchid was in full bloom and quite a shock to stumble on. Most sources show its blooming period as May through July and yet when I found the plant, while in full bloom, it was the first week in April! I saw no others either associated with it in a cluster nor anywhere while on my walk. There were 2 leaves and a single stalk.

Neutral Baa On Oct 7, 2001, Baa wrote:

Terrestrial orchid from North America, Europe and Asia. Has a single, pleated, oblong shaped leaf up to 8 inches long wich grows from a corm. Flowers are 1-1 inches and pinkish purple, large slipper shaped lip which is white spotted purple, pink or yellow.

Flowers in May. Enjoys rich, moist soil enriched with leaf mold or bark chips in a neutral to acid soil in partial shade.

In frost prone areas grow in a cold shaded greenhouse, in warmer regions grow in a woodland or bog garden.

Divide corms very carefully to propigate.


This plant has been said to grow in the following regions:

Chugiak, Alaska
Crescent City, California
Englewood, Colorado
Careywood, Idaho
Cottage Grove, Oregon
Lebanon, Oregon
Lostine, Oregon
Salem, Oregon
Anacortes, Washington
Belfair, Washington

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