Cypripedium acaule

"The Pink Ladyslipper (Cypripedium acaule Aiton) is the most abundant species of ladyslipper orchid in the US. It can be found in colonies numbering into the thousands. 

However, it is also the most-difficult species of ladyslipper to grow in the home garden, if not practically impossible to grow. This is because Cyp. acaule cannot survive in soil with a pH value above 5.0. In fact, it is most often found in acidic soil with a pH between 4.0-4.5. If you are fortunate enough to have these growing on private property, please do not attempt to transplant them off-site, or give them as gifts to your friends. The probability of the plants surviving being transplanted to another site is virtually 0%." 

Cypripedium acaule Aiton, Hort. Kew. [W. Aiton] 3: 303 (1789).

Cypripedium acaule Aiton, Photo by Kevin Holcomb

its native range is Central & E. Canada to N. Central & E. U.S.A.

Latinh Name: 

Cypripedium acaule Aiton

Family: 

Orchidaceae Juss.

Synonym:

Calceolus hirsutus (Mill.) Nieuwl.

Cypripedium acaule f. albiflora E.L.Rand & Redfield

Cypripedium acaule f. biflorum P.M.Br.

Cypripedium acaule f. lancifolia House

Cypripedium catesbianum Raf.

Cypripedium hirsutum Mill.

Cypripedium humile Salisb.

Cypripedium vittatum var. planum Raf.

Fissipes acaulis (Aiton) Small

Fissipes acaulis f. lancifolia House

Fissipes hirsuta (Mill.) Farw.

Fissipes hirsuta f. albiflora (E.L.Rand & Redfield) Farw.

English Name:

Small pink lady’s-slipper, pink moccasin-flower, stemless lady’s-slipper, cypripède acaule.

Description: 

With 2, plicate, opposite, basal, elliptic, obtuse leaves that blooms in the spring and early summer on a terminal, slender, to 15" [45 cm] long inflorescence carrying a solitary, nodding, showy flower arising with the new leaves in the spring in the south through summer in the north.

Distribution:

Alabama, Alberta, Connecticut, Delaware, District of Columbia, Georgia, Illinois, Indiana, Kentucky, Maine, Manitoba, Maryland, Massachusetts, Michigan, Minnesota, New Brunswick, New Hampshire, New Jersey, New York, Newfoundland, North Carolina, Northwest Territorie, Nova Scotia, Ohio, Ontario, Pennsylvania, Prince Edward I., Québec, Rhode I., Saskatchewan, South Carolina, Tennessee, Vermont, Virginia, West Virginia, Wisconsin.

Ecological:

In hardwood and conifer forests, in swamps and bogs, dense woods along streams and in coastal dunes as a large sized, cold growing, erect, terrestrial plant from the higher and drier deciduous forests.

Flowering times:

Apr-Jul.

Flower size:

5.0 cm.

Cultivation:

Keep humidity from 30 to 70%; it is best kept low. Water with distilled or rain water. Keep the mix slightly moist and allow it to dry. The plant is very drought tolerant and does not usually need to be watered. PH levels should be kept at around 3 to 4.5. Plant will die in a couple of weeks if pH is greater than 5. Individuals have used 1 to 1.5 ounces of vinegar per a gallon of water to maintain pH levels. Keep plant in low nutrient soil. Plant should not be fertilized. Grow in full pine duff.

Plants have been grown in beds created by making a 40cm hole and lining the side with plastic but not the bottom. Then 35 cm would be filled with lime free acidic sand with the pH of 3 to 4.5 and the rhizome of Cyp. acaule would be placed flat on top of the sand and covered with coarse pine humus and then with pine cones and needles above that layer.

Type:

Type Herbaria:

holotype BM

Distribution Of Types:

Cultivated at Kew

Cypripedium acaule Aiton, Photo by Bernd Sommer