These terrestrial orchids are rare in an unusual sense: For orchids, Spiranthes sinensis are so easy to grow you may soon have too many of them. They grow from seed so readily that the year after a good bloom you will find them coming up in many of your bonsai pots, looking like a broad-leaved grass—we had so many in some bonsai pots in Japan that we cut them low with scissors to keep them at bay. Which seemed a serious disgrace to such an endearingly beautiful, easy to grow, and cheerful plant.
They are called nejibana, ’screw/spiral flower’, in Japanese. Once when up in the mountains in Japan I saw them growing wild, near the edge of a high pond in wet grass. If you can provide good sun and constant moisture they should grow for you without trouble, and they can take a good freeze without complaint. This is a much more forgiving orchid than the popular if hard to find Egret flower-
Website with more photos and info about spiral orchid: