Symphyotrichum praealtum
willow aster
 
Willow aster is a tall, late-season perennial often reaching 4–6 feet, with narrow willow-like leaves and abundant pale lavender to blue flowers in early fall. It prefers full sun and moist to average soils and performs especially well in meadows and wet edges.
 
The blooms are highly attractive to migrating butterflies and late-season bees. As other flowers fade, this species carries the landscape into fall with energy and ecological purpose — a strong closing act to the growing season.
 
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photo by Kelly Bostian