Cypripedium reginae

Quick Characteristics:

Cypripedium reginae Walter, also named the Queen's Lady's Slipper. This is a tall plant, native in North America, easy to be grown in home garden in a flowerbed with light wet soil in shady position. When the plant is mature, it forms multiple stems of 2 to 3 feet each with 1 to 3 flowers per stem. There is also a pure white form commercially available. Here is a link to the US Forestry service page about this species. Photo from Giorgio Pozzi.