Those are amazing, Flygap!!! On our old place, iris came up all over in multiple colors, too...for the same reason (the prior "lady of the house" liked them). I would dig and move dirt to random places, not knowing it had bulbs in it, and they would even "pop up" in those random spots.
The neighbors told me she would "trade them" w her Iris growing friends and family, which explained why there were so many different colors. It seems to be something Iris growers practice. They do have rather lovely flowers.
Oh, and the little girl is an absolute doll!