I've just been reading about unsatisfactory nurseries, from the big boxes to mail-order and online, and I suddenly remembered another source I've taken for granted for so long I'd forgotten to recommend it, namely plant societies. If you're interested in a plant family an excellent way to find a special variety or a good nursery source is from the society dedicated to that plant family. For instance, daylilies are usually sold, even in some non-specialist but very reputable nurseries and catalogs, as growing in z3-9. Well, it's true that some daylilies will grow in z3 and some will grow in z9, but they are seldom the same varieties. I bet lots of people have been turned off by daylilies after they got some suitable for the wrong zone. Also some generalist catalogs sell once-blooming daylilies for very high prices that were superceded years ago by ones that re-bloom, sometimes for the whole summer, and that are fragrant and open evenings. Also, the specialist growers in the society will often sell better plants for much less, as the real daylily addicts have to have new ones every year, but if you wait three or four years the prices come down dramatically for many of them. The same is true for iris, and I'm sure most plants with their own societies, tho' not some of the ones I'm most interested in, naturally! But at least they'll have a much wider range of plants you might never hear of without their advocacy.