This is a white Siberian Iris. cast iron, like all of the varieties of Siberian Iris. Not a large flower, it makes up for its diminutive size by being prolific. When a clump gets established you can have dozens of blooms on a clump. It will grow almost anywhere, but loves nice soil. Alberta Burrill gave me a clump from her house at 60 High Street in Houlton, Maine. Alberta was my brother-in-law's mother.