- Dormant. The leaves of these daylilies die completely back as winter approaches. They stop growing and form resting buds at the crown, and the foliage dies down naturally and gradually. In the spring, the resting buds have a distinctive spear-like appearance as they emerge.
- Evergreen. These daylilies retain their leaves throughout the year. They do not form resting buds. Instead, they continually produce new leaves unless cold weather prevents growth. In mild climates, the leaves of evergreens remain green all winter. In the coldest climates, the foliage of evergreens nearly always is frozen back, but the crown survives if it is hardy (or well mulched).
- Semi-Evergreen. Today, the term semi-evergreen is used to describe any foliage behavior that is not readily classed as simple evergreen or dormant. Originally, the term semi-evergreen (or conversely, semi-dormant) was used to describe those daylilies that retained many of its leaves and appeared somewhat evergreen when grown in the South, but lost all its leaves and went dormant when grown in the North.
Another registered evergreen that goes dormant in colder climates, Challenger is a Stout cultivar from 1949 that is a blending of H. altissima and H. fulva, both of which show this type of foliage habit being evergreen in warm climates and dormant in cold climates.
While it is true that the H. fulva clone Chengtu shows leaves that remain green through cold winters yet develops resting buds, the cultivar I am referring to did not show what I would call resting buds, any more than did Great White, growing beside it. If it was a dormant then so was Great White. None of the evergreens growing here in a normal or hard winter grow new leaves (unless we have an occasional warm spell out of season) and a great many of them don’t have nearly as much green foliage above ground as this ‘dormant’ did. Further, it doesn't match the AHS registration definition of a dormant. I don’t grow this one any more because it turned out to be extremely susceptible to rust, but the foliage habit would not have been any deterrent to me buying or using the plant.