By definition, a semi-evergreen daylily behaves like a dormant in the north but acts like an evergreen in mild, frost-free climates. Semi-evergreen daylilies theoretically perform reasonably well in both Southern and Northern gardens. In reality, however, the semi-evergreen classification may be considerably more complex. Semi-evergreen daylilies possess foliage that is slower to die back in the fall than that of dormant daylilies. Usually, a few green shoots, 2 to 4 inches tall, remain visible even after exposed to quite severe cold. These tips become mushy after successive freezes but, unlike evergreens, the main body of old foliage on semi-evergreen daylilies dies back completely in the winter. Although there is always new growth at the center of each foliage fan, it is not as persistent as it is in evergreens. Semi-evergreens are often quicker to re-emerge in the spring than are dormant daylilies.