The Alabama Cooperative Extension service suggests pairing purple fountain grass with purple coneflowers (Echinacea pupurea). These sturdy wildflowers have pinkish-purple, daisy-like flowers with a prominent central cone. Butterflies and birds love purple coneflowers. Their upright habit makes a strong contrast to purple fountain grass' arching form. Purple coneflowers grow 2 to 3 feet tall and bloom from mid-summer until frost. The cultivar White Luster has white petals around an orange cone. Echinacea is hardy throughout Zones 3 to 9.
Tickseed (Coreopsis) gets its common name from the tiny, black seeds resembling ticks. These hardy perennials have yellow, daisy-like flowers throughout most of the summer. Threadleaf coreopsis (C. verticillata) makes a clump of finely divided foliage topped by small, yellow daisies in early summer. When flowers fade, shear the plant back to 12 inches to encourage reblooming. The cultivar Moonbeam grows 18 inches tall and has lemon-yellow flowers. Zagreb is similar, but with golden yellow flowers. Coreopsis grandiflora is a more substantial-looking plant, with 2- to 3-inch flowers, often with a darker eye. Deadhead faded flowers to keep it blooming all summer. Plant both types of coreopsis in full sun or light shade. Hardiness depends on cultivar, so read plant labels carefully, but most tickseeds are hardy in USDA Plant Hardiness Zones 4 to 9.
Wormwoods (Artemesia) are a large group of plants grown mainly for their silvery foliage. The hybrid variety Powis Castle forms a 2- to 4-foot mound of ferny, gray-green foliage that contrasts beautifully with the dark foliage of purple fountain grass. The foliage stays attractive in mild winters, but old stems should be cut down in late winter or early spring. Wormwood is hardy to USDA Plant Hardiness Zone 5.