I want to stress that I do not advocate any notion that all cultivars of any given foliage habit are 'good' or 'bad'. All daylilies have a place and all are right for some environment. The point of discussing foliage habit is that all daylilies don't work in all environments, but I personally believe that there are fewer that will fail in any given environment than will succeed. However, there are definitely some evergreen types that will either fail or perform poorly in cold climates and there are some dormants that will fail or do poorly in perpetually warm, southern climates. These are simple facts, and they are no attack on anyone.
With this disclaimer out of the way, I want to stress that one problem I keep seeing from every side and corner in the foliage habit discussion is the tendency to generalize. I see people say that all dormants are hardy, or that all evergreens are tender. Some say that all dormants are frost resistant, while all evergreens are frost susceptible. However, none of these things are true. I can't stress this enough. There are no possible blanket statements that can include 'always' or 'never' when we are discussing foliage type. It is a common human tendency to generalize, but it almost always misses the mark, because almost nothing in life is black or white. Life is shades of gray and this is also true of foliage habit.
So I want to dismantle these generalizations and encourage people to look at the nuances we see in each and every cultivar. Finally, it is important to remember that all cultivars are not necessarily accurately registered for foliage habit, while some cultivars perform differently than they are registered for foliage type in environments different from the one they were grown and registered in. This often isn't any attempt at deception, it is just the nature of the beast. Daylilies can be highly variable depending on the environment and can perform very differently for foliage type when moved around the continent.
'All dormants are hardy and all evergreens are tender.' FALSE! There are tender dormants and very hardy evergreens. However, both of those examples are in the minority, but they do exist. The tender dormants are probably the rarest of the two things, and there are a good number of evergreens that are perfectly hardy. However, all evergreens are not hardy. The only way to know which dormants are tender or which evergreens are hardy is to either grow them and see what happens or to talk to people who have grown any cultivar you are considering in an environment similar to yours. And I must stress again - similar to yours. If you are in zone six or seven, there are evergreens that will do better further north or further south than they will for you, because the heavy snow cover throughout the winter in more northern areas insulates the plants from the extreme cold and drives them into a state not unlike dormancy. Yet in the more temperate yet still cold zones there is little to no snow cover for much of the winter, thus plants are exposed to drying, desiccating winds, extreme variations of temperatures including warm spells followed by cold spells and these can be exceptionally destructive to plants that might otherwise perform much better in both warmer and colder areas. So be sure you talk to people in a climate similar to yours to determine how a given cultivar might work for you. Your other option is to simply try the plant and accept the possibility of loss or poor performance.
'All dormants are frost resistant, while all evergreens are frost susceptible.' FALSE! Both statements are generalizations and not true. In my garden, I see a wide range of frost resistance/susceptibility and it isn't dependent on foliage type. I have registered cultivars and seedling that are evergreens, which show frost tolerance and I have registered cultivars and seedlings that are dormant, which are frost susceptible. There is no apparent linkage between foliage type and frost tolerance levels. It is so important to remember that each cultivar must be judged individually on not just on the registered foliage type.
So with that out of the way, let's look at a few of the cultivars I showed pictures of in my blog post from 12/23/2014. This first group of pictures were taken on March 22, 2015.