I've been growing this tiny Iris in my gardenfor ten years. Iris lacustris 'Alba' is a dwarf lake Iris native to the shores of Lakes Huron, Michigan and Superior and thus adapted to harsh and exposed growing condition. It typically grows in gravel — unlike its woodland relative I. cristata — and so that's where I planted mine.
In the last few years moss has been spreading outward from the hard clay path into the Iris gravel. I may need to move the Iris as I don't think this much moist moss is going to be good for it. But I love the look!