Big Bluestem
Andropogon gerardii 'Blackhawks'
This plant fills a space rather quietly in the early season and by late summer the grass will fill in with dramatic height and colour. The almost black blades, make this one absolutely striking in late summer.
It will become quite dominant in late season by year two, so make sure you give it lots of room. I made the mistake of putting it beside a path and it took over that path by August.
Going strong at five years.