My new favorite perennial (for autumn) is:
Look at all that brilliant yellow!
These plants are now about 18″ tall and, knowing I just planted them in April, I am amazed. Most perennials take a year or two really develop, but these have taken off. They are in full sun and receive water from my watering system every other morning for about 45 minutes. We’ve had a very VERY hot and dry summer and they have flourished.
Above, with the Scabiosa Black Knight behind them
Here, looking glorious with the dark red dahlias!