Dwarf Sweet Flag (Acorus), grass-like perennial, 2-4 in., slow clumping spreading growth habit, fan-like clusters of tiny dark green leaves, full sun to light shade, best with regular water, excellent between stepping stones, tolerates light foot traffic and boggy conditions. Taller varieties also available.
Sweet flag has long been known for its medicinal value, and has been cultivated in Asia for this reason. The species Acorus calamus is native to the southeastern United States, growing in wet areas in marshes and ditches. It looks rather grass-like, until closer inspection reveals the arum-like cluster of flowers.