Masses of vibrant, true royal blue flowers with violet overtones bloom on tall, sturdy spikes from late spring through summer, opening from the base upward. Deadheading spent flowers can encourage continuous reblooming. It is an herbaceous perennial with a naturally compact, upright, and clump-forming habit. It typically grows 14-18 inches (36-46 cm) tall with a spread of 14-17 inches (36-43 cm).