Adam's Needle (Yucca filamentosa 'Color Guard') and Little Bluestem Grasses (Schizachyrium scoparium 'Standing Ovation'). Yucca is native in the southeastern United States and is evergreen. Bluestem Grass is native to prairies all across North America, the 'Standing Ovation' cultivar is noted for its flop-resistant upright habit.
Kalimeris incisa 'Blue Star' and Blue Fescue (Festuca glauca 'Elijah Blue'). While neither of these plants are natives they are not without merit! Each thrives in hot, dry, poor soils. The 'Blue Star' Kalimeris is a reliable mid-summer bloomer (its aster-like flowers are just getting started here), and the 'Elijah Blue' Fescue persists as a tidy blue-grey clump all year providing great winter interest when other perennial grasses are dry and brown.