I grow dormants in So Cal and have a different take on them in my zone 10b garden. My best increaser by far last year was a dormant but so was my worst (although it put on a spectacular show during bloom season) so I don't let foliage habit influence my purchase decisions too much if at all (I do, however, note if it is listed as a "hard dormant"). I order from around the country and have found that, although some cultivars may take a year to settle in, they all do acclimate (I believe that the vast majority of dl's that I have are from colder climates). The only issue I have had is that a handful of cultivars seem to detest the extreme heat (we can get 115-117 degrees in summer) but this has been on a cultivar to cultivar basis - not related to where I purchased the daylily from. Because you are in a fogbelt (you are so lucky!), that probably won't be an issue for you.
This year, the bulk of dl's came from northern growers as I am trying to lessen my chance of getting rust introduced. I make sure I take receipt in the early spring, also - just as they are breaking dormancy if they are dor's - and before the nurseries are getting in their dl's for the season. Also, I quarantine the new arrivals. So far, I have been lucky and there is no rust
