Cypripedium acaule

Common Names

Pink Lady's Slipper, Moccasin Flower, Lady's Slipper Orchids, Stemless Lady's Slipper, Slipper Orchid, Pink Lady's Slipper Orchid, Moccasin Orchids

Summary

Cypripedium acaule, the Pink Lady’s Slipper or Moccasin Flower, is a North American orchid with a creeping rhizome and two basal, veined leaves, flowering on a leafless stalk, plants reach about 15–61 cm tall and bear a single pink slipper-shaped lip, with sepals and petals colored brown-green to purplish and often twisted; the lip ranges magenta to white with darker venation, native to eastern Canada and the United States, it grows in a broad range of dry to wet forests, bogs, brushy barrens, heath, and roadsides on highly acidic soils, frequently forming large colonies and showing the characteristic stemless flowering habit, cultivation requires indirect bright light or partial shade, protection from direct sun, and an acidic, well-drained, humus-rich medium with soil pH below 5 (ideally 3.5–4.5), a cool root environment is beneficial; maximum summer temperatures should be under about 26°C and winter nights around 4–7°C, with humidity about 50% and media kept evenly moist but not waterlogged, water must be rain or distilled water; repotting every 4–5 years; propagation by division during dormancy; germination depends on a mycorrhizal fungus; natural germination can take many years; transplanting from the wild is difficult and often legally restricted; hardy in USDA zones 3–8; fertilize sparingly in spring, then stop during dormancy, and manage for long-term establishment which can span decades.

Lifecycle

Perennial

Height

6-24 inches

Spread

9-12 inches

Hardiness Zones

Zones 3-7

Sunlight Requirements

Ideally partial shade.

Soil Type

Acidic, moist but well-drained, humus-rich soil

Soil Drainage

Acidic, well-drained soil that stays moist but not waterlogged.

Soil pH

3.5-4.5

Bloom Color

Pink to white; blooms range from pink to purple, with white forms relatively common

Bloom Time

Spring and Summer

Foliage Color

Green

Leaf Lifecycle

Deciduous

Growth Rate

Slow

Seasons of Interest

Spring, Summer, Fall, Winter

Propagation Methods

Seeds, Division

Attracts Wildlife

Attracts bees