Veronica is easy-to-grow and may be the longest-blooming perennials in your garden! More perennials: http://www.bhg.com/gardening/flowers/perennials/the-best-perennials-for-cutting/?socsrc=bhgpin091913veronica#page=20
PERENNIAL - Pincushion Flower Pincushion flower, or scabiosa, serves up dainty blue flowers all summer and into fall, making it one of the longest-lasting bloomers in the perennial bed. It likes sun or partial shade, and is best at the front of the bed. The foot-tall variety 'Blue Butterfly' stands up to heat best.