I've used a bulb fertilizer on mine, Happy Frog 5-5-5, but I have very poor soil.
I do have one native heuchera that I had ignored for years because I didn't know what it was. It picked up dramatically when I gave it a light feeding and some water during the summer months. It is sited on the north side of my house. Oh, and it is also no longer being regularly deer chomped.
All of my plants survived a long drought, so they are pretty good surviors.
