You know, I don't think anyone mentioned calla lilies and cannas. And don't forget about peonies, fabulous as cut flowers, and some are fragrant! Plus they are easy to grow, and are a very long lived perennial. Oriental lilies are the ones with scents that make you swoon. There's also turks cap lilies. And don't forget about iris!
The thing to planning a perennial cutting garden is to plan for something to be blooming all the time…. And so you see the procession of the very early, like snowdrops, star of Bethlehem, to daffodils and narcissus, then iris, blooming shrubs such as spires, wisteria, roses, cone flowers and salvias, then late in the fall, asters and echinaceas again.
A lot of folks have a beautiful bloom season in the spring, but neglect to plant later bloomers. And the nurseries and box stores buy into this by what they offer in the spring.
Another good group of plants to explore are natives; they often have a long bloom season.
