Kansas Gayfeather is a great-looking plant, except that the flower stalks don't remain upright very long.  Usually, they just lay on the ground.  It is supposed to bloom for a very long time, but I wouldn't know about that.  I have had only one good bloom in the six years that it has flowered, and that didn't last very long.  Most sources list it as growing 4' tall and higher.  However, mine have never grown much taller than 2'.  It's supposed to attract butterflies, but I've only seen one on it so far.