If you're in the New York metropolitan area for the next 7 days, you should definitely visit the Presby Memorial Iris Gardens in Upper Montclair, New Jersey. They are utterly spectacular this year.
It's the 80th anniversary of the gardens, and the gardeners have placed new placards in front of each plot that state the years the irises in that plot were initially cultivated and/or collected. They even have a few from 1500!
My entire Picasa Web Album of the gardens is here (mind you, the first few photos are of my garden).
If you don't feel like viewing the entire display, here are a just a few of my favorites: