Of all perennials, daylilies are among the easiest to grow and care for. They're as undemanding as they are attractive, and even the greenest novice can succeed brilliantly when growing them. Most daylilies are tough as nails, and don't really require much of anything in the way of winter care in order to survive. Even the most rugged of cultivars will benefit and bloom better for you if you take a little time and effort to provide them with some winter comfort. Put your winter preparations in place before the first expected freeze for your area.
Collect and destroy seed pods as they appear on your daylilies prior to freezing weather. Otherwise, they'll self-seed themselves prolifically. This isn't entirely a bad thing, but keep in mind that your daylilies are hybrids and the offspring will be unpredictable, at best.
Pull summer mulch back from daylily stems. The mulch should clear them by at least an inch.
Examine the old foliage carefully as it dies in late fall. Look for black spots about ¼ inch in diameter. These are fungi called sclerotia, or leaf spot fungus, preparing to over-winter on your daylilies. Cut the foliage back to the ground and destroy all vegetative refuse. If the plants are clear of fungus, leave the foliage in place to provide a measure of natural protection for the plants.
Cover your daylily bed with a generous layer of mulch right before the ground begins to freeze. Mulch the area to a depth of 2 to 6 inches for established plants, 10 to 12 inches for new plants and fresh divisions in their first year. Use hay, straw or hardwood leaves, but don't use softwood leaves. Those will mat easily and kill your plants.
Water your daylilies about once weekly during the winter, but only if you've had no rainfall.
Remove the winter mulch and old foliage in the spring when freezing weather is no longer predicted. Wait and watch for elms and soft maples to begin blooming--from February through April, depending upon your location.