The Seslaria genus of grass, named to honor the famous 18th century botanist Leonardo Sesler in case you didn't know but were dying to, is a fantastic perennial evergreen grass that loves sun and shade. It's needs are simple, so its an excellent choice for a wild, natural look where you are looking for a dominant grass in a small space in an informal way. Plants you might consider to pair it with are Achillea, Wild Geraniums, or Potentilla.
Conditions: sun and shade
Water: little amounts required