I grow Iris unguicularis in an outdoor but protected (slightly under the overhang of the deck) spot, on the leeward side of the house, and there it has grown and flowered with almost no care at all for about 10 years. It has survived temperatures down to 5 degrees F (about minus 15 C) without added protection, but the deck keepts it dry. I water it when I remember to. There is a somewhat hardier species closely related to it and very similar in appearance, but flowering later in the winter Iris lazica. It is not, however, as fragrant as I. unguicularis. There was a nice article on I. unguicularis in an issue of the Rock Garden Quarterly about a year ago. Jane McGary Northwestern Oregon