It is a stroke of luck that the crossing of the common yellow lis, Iris pseudacorus x I. sibirica, native to us, produces such a special and beautiful result.
Both Iris species originally growing in water are perfectly hardy and planted along the edge of a ditch or pond, but also in the open ground of the garden, they can be a feast for the eyes during the summer months in full bloom, especially if you can grow into sizeable clumps after years.
Highly recommended of this rather rare plant.