Bearded irises are best planted in summer or fall, no later than six weeks before your area's first freeze. Situate the rhizomes just at the soil surface with the roots spread out underneath. "Like a duck," Lohr says. "Their feet are in the water but their back is above."
Irises "don't take much mollycoddling," says Boyce Tankersley, director of living plant documentation at the Chicago Botanic Garden in Glencoe, Illinois, who grows a number of historic varieties at home. "I don't spray them, I don't fertilize them any more than I fertilize anything else, and they keep coming back and giving me a good show."