Northern sea oats (Chasmanthium latifolium), a perennial grass native to North America, is a favorite among gardeners for its delicate spangles of oat-like seed heads on nodding stems. The variegated cultivar ‘River Mist’ (pictured here) is a newer variety. To the charms of the species, it adds dazzling green and white stripes on the leaves. Seed heads of white and palest green turn bronze in autumn. Grows 30 to 36 inches tall. Zones 5 to 9.