From Tony Avent's wonderful essay on growing hardy ladyslippers ...Read Morerchids" target="_dgnew"rel="nofollow">http://www.plantdelights.com/Article/Cypripedium-Lady-Slippe... :
"This strain of hybrid lady slipper orchids was developed in 1996 by Germany's Werner Frosch by crossing the Chinese Cypripedium macranthos with the American Cypripedium parviflorum var. pubescens. The heat tolerance of the Cypripedium parviflorum var. pubescens allows gardeners in warmer climates to have success. The hybrids, which display amazing vigor, emerge in late spring forming 18" tall stalks topped with large plum to pink striped flowers, each highlighted by three twisted pinkish sepals. (Hardiness Zone 4-7, probably colder)"
From Tony Avent's wonderful essay on growing hardy ladyslippers ...Read More