I live on the Alabama Gulf Coast 1/2 mile from the water across the bay from Pensacola Fla. I don't believe any daylily here ever stops growing. I bloom seedlings (from seed to bloom) in 7-8 months, the two year old seedling seem to do more increasing in the winter than any other time and most of them bloom at their normal time (May and June). We have had much worse winters than this year but never seemed to effect the growth of the daylilies. This photo was taken yesterday 2-24-19 and there are very few dying leaves. Will try to get some close up photos today.