Fresh irises are one of the more difficult cut flowers to keep. You bring them home, arrange them in a vase, and for two or three days they look exactly as you hoped. Then the petals begin to thin at the edges, the outer falls start to droop, and within a week the arrangement is finished. Even with fresh water and proper trimming, irises rarely last longer than five to seven days.

These do. Place them in a vase today and they look the same three weeks from now, and three months after that. The layered petals hold their position. The upright falls stay open. The green stems and leaves stay firm. A handful of them in a wide vase creates the kind of full, garden-style arrangement that used to require a florist trip every week.