goedric said:True, but it is listed as hardy zones 4-9 on their website. Plus there is a thread here on dormancy. etc which discusses that fact that the generally accepted convention of using EV/SEV/DOR as a proxy for cold tolerance is no longer accurate with modern day hybrids... It's a great article written by Maurice that is well worth reading. In fact I need to read it again!
Thank you. I must also add that the registered information is how the plant grows in the hybridizer's location and growing conditions. I am in zone 4. I buy daylilies without even bothering to notice the designations and I have often bought direct from Florida hybridizers. Many Florida-hybridized cultivars registered as "evergreen" act the same as "dormants" here - they go winter dormant. A few do not, but most of those tend to be hardy. A few from certain lines are iffy.
It is important to understand that although the "evergreen"/"semievergreen"/"dormant" registration labels are not highly correlated with winter hardiness, daylilies that have been hybridized in locations that do not have the same winter conditions as where they will be grown have no selection for the necessary level of winter hardiness. There can be carry-over of previous selection pressures, for example where a southern-hybridized (mild winter) daylily has some ancestors hybridized in cold winter locations but the more generations that occur in the mild winter location (without use of cold winter parents) the less adapted the mild winter bred daylily will be to cold winters.
It is also important to understand that the ability to become winter dormant (endodormant) is probably not genetically the same as being cold hardy to any specific low temperatures. The lack of winter dormancy and winter tenderness were probably associated in
Hemerocallis aurantiaca var
Major (not particularly hardy in New York) but not genetically as the (possible/probable?) first generation hybrid
H. aurantiaca (an "evergreen") was hardy in New York.
