Roses bring the drama, and drought-tolerant grasses bring the cool confidence. Put them together, and a garden bed suddenly looks less like a collection of individual plants and more like a thoughtfully designed landscape, with lush flowers rising above ribbons of foliage that move when the breeze wanders through.
There is a practical reason for the pairing, too. Many ornamental grasses handle dry conditions with considerably less fuss than thirsty bedding plants, while roses still provide the flowers, fragrance, and color that make a garden feel abundant.