Linda: You made me smile. No I did not get rid of all my dayliles that weren't dormant. Because all my plants have been in the garden for over many very cold winters, 100% have gone dormant. 'Dormancy' simply put means all the foliage dies back to the ground during winter. The plant then forms new leaf buds at the crown of the plant. As opposed to 'Evergreen' where the foliage above ground remains green and alive throughout the year. It may stop growing in colder weather, but the plant attempts to keep its leaves going. Usually, for the most part, the more dormant a daylily is, the better it will live in colder climate; and along the same lines, daylilies that are more evergreen will not grow as well in colder climates. Those evergreens are the plants we 'baby' each year as we close our gardens for Winter. For nearly 80% of daylilies, their foliage truly represents their hardiness. But as with everything in life, Linda, there are exceptions to the above.
Hard Dormants- These plants die well into the ground and form hard buds during winter. You can poke your fingers into the ground and feel something that feels a lot like a hazelnut just beneath the surface. These daylilies are truly the hardiest of all, and have been known to survive in certain areas of a zone 3 climate.
Soft Dormants- These plants die back to ground level and form buds that can sometimes feel a bit squishy. They do not shut down quite as well as hard dormants do. There growth also appears earlier in the Spring, and as a consequence are suseptible to late frosts, a problem we all face here in the Northeast.