When it comes the shades of blue and purple, I also like this Salvia greggii 'Purple' Autumn Sage I found at Wal-Mart for $5. Salvias are good plants for Southeast Texas, and this perennial will grow about 3-feet tall and 2-feet wide.
I'd pair it with a Sapphire Carpet Sage (salvia de alfombra de Zafiro), a clump-forming perennial that needs full sun but has low water needs.
