This is one of my absolute favorites!  The small (approx. 2″) bloom is only open for a day, but then followed by other blooms.  It is in the iris family, so the leaves are tall and similar looking.  Following blooms the seed pods will turn to a fruity looking seed pod that resembles a blackberry, so they have good fall interest as well.  Once established, it is drought tolerant– liking well drained soil and sun to part shade.