Hoary Vervain (Vernonia fasiculata) is a seasonal plant with lavender blooms from mid- to late summer. They prefer mesic soil in full sun where they grow up to 4 feet tall. They are a good choice for sunny banks and slopes. Companion plants include Palm Sedge (Carex muskigemensis) and Ohio Spiderwort (Tradescantia ohiensis).
No serious maintenance needs.