Day lily varieties in colder climates may see all leaves die back completely in winter. Others types are semi-evergreen and still others, such as tropicals, are evergreen. Many plants sold today are hybrids and come in many colors such as yellow, purple, pink, red, green, orange and more. Also, there is much variation in the size and shapes of blooms. Most are tolerant of a variety of soil conditions although a nice fertile mix will hold moisture better.
Moisture is good but a well drained site is required.
Light fertilization is best otherwise you get too much foliage at the expense of more flowers. Fertilize in the early spring then once more after blooms have stopped to help next season's start. Also, it is best to cut spent flowers to encourage more to grow. The Friends of the Daylilies website has pictures of many varieties. You may be interested in receiving great tropical plants mail order from Master Gardener.