I'll tell you my little daylily abuse story that to me is amazing.
I had about 40 of the 18oz red cups that I had grown seeds in from 2006. These were seedling that I recieved as bonus seeds and few of my seeds that I didn't really want. I just couldn't throw away, so I planted them in the red cups back in 2006. They stayed in the greenhouse all that winter with my other seeds but I never got around to potting that 40 up into bigger pots that Spring. So, I set them in a tray outside under my big old oak tree. Remeber 2006!!!! They did get a little watering when I would water the group of pots that were close to them that summer and fall. Along came winter of 2007 and they are still outside in these 18oz cups. Fast forward till 2012. Yeap, I didn't get around to potting those 40 cups up until last week. Only 28 of the 40 lived, but still for 5 years that survived summers of 105 degrees in those cups and lived. Then winters sometimes below 10 degrees and they lived. When I was potting them up last week, I found that 3 of the cups had actually grown from 1 plant to 3 plants and they were about the size of a small straw, the coffee stirring straw size.
So, yes, daylilies are very hardy plants!!
Now, you know my worst case of abuse on my daylilies. It'll be interesting to see if those plants will actually grow now that they have the proper pots, fertilize and mulch.
Blessings, Mona