I initially came across this plant blooming enthusiastically in a dry meadow at the tail end of a very dry summer, and knew I it was something I had to try to grow. It really focuses on flower production, and has become one of my all-time favorite asters.
 
Western aster is a rhizomatous perennial with medium-height stalks that are covered with purple-ish flowers with yellow centers late in the summer. It tolerates a wide range of growing conditions and soil types as long as they are well-draining. While it can handle full sun, it will be taller and showier if provided protection from late afternoon death ray sun (for example, I often find it in clearings in cottonwood galleries, where the trees cast evening shade).
 
Interestingly, I frequently find it growing among smooth brome...not dominating it but persisting, which is impressive (smooth brome is a total bully of a non-native grass). Western aster would do well in a restoration planting, naturalized meadow planting, or edge of a thicket. Because this species is rhizomatous, make sure it has some room.
 
Some good companions include: chamisso sedge, white sage, hairy goldenaster, curlycup gumweed, snowberry, woods rose, and white prairie aster.