That is good to know about the depth. I have heard that you shouldn't plant daylilies deeper than the top of or 1" below the crown (where the roots and the leaves meet). Too deep and they don't bloom very well and can get crown rot.
Fred - My newest two beds are about 12" deep, I was wondering if that was going to be deep enough. Thanks for mentioning about your roots never growing deeper than your 9 1/2" depth.
