Blue-eyed Grass is related to the iris.  I found it growing wild in my lawn one year.  My lawn mower had broken down and the grass grew a little high.  I saw this blue flower that looked like it was growing out of the end of a grass stem (hence its name).  I pulled some of the other grass away from it and let it grow.  It grew into a 14" tall plant.  I moved it into my garden where grows up to 10" tall, and reseeds itself freely.  It begins flowering in mid-May, and will bloom into August if the round seed pods are removed.  If dug up, it will easily separate into many smaller plants.