Blanket flower (Gaillardia aristata) has mahogany-red petals tipped with golden yellow that bloom all summer long. The handsome flowers are perfect in a mixed bouquet, but left in the garden, they are a great attraction to the variegated fritillary in search of nectar. Once established in average garden soil, sun-loving blanket flowers are quite xeric (drought-tolerant).
Great Plains verbena (Verbena bipinnatifida) is another long-blooming wonder plant. Adapted to extremes of heat and cold, this perennial groundcover is excellent for fall planting. Butterflies such as the checkered skipper gravitate to the sun-drenched, magenta-pink flowers and their abundant nectar.
As important as the nectar plants that feed adult butterflies, host plants such as dill and parsley serve the voracious caterpillar stage for this region's black swallowtail butterfly. Some plants, including milkweed (Asclepias spp.), provide nectar for adults and food for many different caterpillar species. Blue flax (Linum lewisii), with its true-blue flowers, is a host plant of the variegated fritillary. Suited to the cold climes of the Rockies and the Great Plains, blue flax blooms from late spring through summer and can reach nearly 3 feet. Just overlook any plant damage during the caterpillar stage, and be rewarded with a bevy of butterflies.