These bright yellow blooms are very autumnal.
A number of years ago, one of our neighbors was having these pulled out of her flower garden, so I asked her if I could have some. The tubers transplant very easily and these things will take over (which is why she was ripping them out). I now have them in four places around the property. They're pretty low maintenance and don't require watering beyond what rain they get (unless it doesn't rain at all, then some watering helps).