It isn't a commonly available cypripedium. It is rarely offered for sale - and when it is listed for sale it tends to sell out quickly.. I read that it needs alkaline conditions, well draining soil and it starts growing very in the season and can get frozen back in its early stages of growth. It is for zones 6 to 8.

Start looking for it when nurseries first start listing their plants for sale, usually around the beginning of the year - January or even earlier.

If it is so easy to grow why don't more nurseries that offer cyps have it for sale? Something tells me that it isn't quite as easy to grow as you might have read or else it would be available more often. That or it doesn't grow very fast from being a seedling or multiply much as an adult plant. The common Yellow Lady's slipper is an easy cypripedium to grow, as are some of the hybrids.

Sorry I couldn't be of more help. Good luck with your orchid quest!