I really think the size of the pot is important to the conversation. A half-barrel will give you much more success than a small pot that you need to water all the time. The more soil, the better the plant will do in most cases. And I think nearly any daylily will do well if it survives the first year. The closer to the wild plant, (known as ditch daylilies or something like that) the better it will do in suboptimum conditions. I got a clump of those, and every other daylily turned brown and died back, but those wild types kept green and are huge now. I have also usually gotten my daylilies at garden centers. I know you get less choice, but you often get very healthy plants that have a lot of hands. When I've bought plants from online venders, they usually send a tiny skimpy piece and I often lose them, which is why I gave up buying plants online and will go to the nursery and pay more for a well-established plant. At the nursery, you also can see the plant in bloom.
