Liatris is a North American native.  Also known as Gayfeather or Blazing Star, its leaves form long grass-like clumps.  They are known for their long-blooming 4-5" vertical spikes which have numerous rosy-purple or white tiny flowers that bloom from top to bottom.  It tolerates very dry conditions and grows large clumps that divide easily and will also self seed.  It has a neat and predictable habit, and it doesn't seem to mind being moved.  A bee and butterfly magnet.  Hardy down to Zone 3.