I think a lot of the hardiness issue depends on if you have reliable snow cover or not. We tend to have the cold without the snow and can't grow things that people in colder areas can grow. I see Cassa on the LA growing things up in Canada year after year that are impossible here. You might be able to grow things there in Minnesota that I can't grow in Ohio, so that makes it much more difficult to lump things in one basket. I think soil type also has a big influence in what we can grow. My soil is sandy loam, but my friends have heavy clay. They have a harder time with some plants, and they are just a few miles away.
My suggestion is for you to try to visit other gardens in your area to get some idea of what might grow well there. We have such a diverse selection of daylilies for all areas. As for me, myself, I just normally buy whatever I like and take my chances.... but I usually avoid evergreen plants unless I am using them to make crosses with hardy ones. As I said, I think reliable snow cover is the key- unless you are mulching with something else. I normally don't mulch anything here.
