There are two types of awards given to Irises by The American Iris Society: Garden awards and Show awards.
Garden Awards are recommendations to the public that an Iris is a worthwhile plant for their gardens. This is a tall order because the microclimates across American vary enormously. So despite a plant having received an award it is always wise for someone to check with their local AIS affiliate on how it performs near them. Nonetheless Irises are amazing, highly adaptable plants, and mostly a garden award is a good indicator of the best Irises for your garden. AIS Garden Awards include:
Show Awards are given to specimens at shows that give the best presentation at the show. Some Irises make beautiful show specimens but do not provide the length of bloom that a good garden Iris would provide.
-- BobPries - 2012-07-08