Narrowleaf Mountain Mint (Pycnanthemum tenuifolium) is a structural plant with white flowers from mid-summer to early fall. They prefer moist to dry soil in full sun where they can grow to 3 feet tall. They're best suited for sunny slopes and basins. Companion plants for this species include Grey-Headed Coneflower (Ratibida pinnata) and 'Shenandoah' Switch Grass (Panicum virgatum 'Shenandoah').
No serious maintenance needs.