Iris relatives with narrow, grasslike leaves and small, six-segmented flowers that open in sunshine. The blossoms are pretty up close but not showy from a distance. Best suited for informal gardens or naturalizing; small types are good in rock gardens. Easy to start from seed; will self-sow. Not usually browsed by deer.
S. angustifolium. COMMON BLUE-EYED GRASS. Zones US, MS, LS, CS, TS; USDA 6-11. Native to North America. Grows 618 in. tall, 6 in. wide, with dark green leaves and clusters of 12-in. blue blossoms in summer. 'Lucerne' is 810 in. tall and bears large, bright blue flowers over a long period; 'Mrs. Spivey', with pure white blooms, may reach 212 ft. tall. 'Suwanee', which may be a hybrid, is a compact grower to about 8 in. tall; vigorous and adaptable, with a profusion of sky-blue flowers. Moderate to regular water.
S. atlanticum. ATLANTIC BLUE-EYED GRASS. Zones US, MS, LS; USDA 6-8. Native to eastern U.S. Violet-blue flowers with yellow centers are carried on slender, wiry, branched stems that range in height from 4 in. to 212 ft. tall. Plants reach 68 in. wide. Pale grayish green leaves. Blooms from late spring into early summer. Regular water.
S. striatum. ARGENTINE YELLOW-EYED GRASS. Zones MS, LS, CS; USDA 7-9. Native to Chile, Argentina. To 3 ft. tall, 1 ft. wide, with attractive gray-green leaves. In spring, produces spikelike clusters of many 12-in. flowers in pale yellow streaked with brown; blooms well into summer if old flower clusters are removed (if you don't remove them, you may have hordes of unwanted seedlings the next year). Leaves of 'Aunt May' ('Variegatum') are striped with creamy yellow. Moderate water.
S. tinctorium. MEXICAN YELLOW-EYED GRASS. Zones US, MS, LS, CS; USDA 6-9. From Mexico and South America. To 1 ft. high and wide. Narrow, blue-green leaves; light yellow, 34-in. flowers from early spring into summer. 'Puerto Yellow' has bright yellow blossoms. Moderate to regular water.