Liatris – an herbaceous perennial with feathery flower plumes of bright purple or white that bloom in mid to late summer.  
 
Growth: Can grow 1 – 5 feet tall.
Light: Prefers full sun, but can tolerate light shade. 
Soil: Requires good drainage to avoid root rot.
Hardiness: Rarely susceptible to insects or diseases, but can experience powdery mildew without full sun, drainage, and airflow between plants. 
Maintenance: Low maintenance, though they might require watering during drought periods.  
Benefits: Attracts migrating butterflies & hummingbirds.