A spring or fall planted bare root tuber plant: Vigorous and prolific, Day lilies takes winter cold in the north and summer sun in the south. They are the plants every gardener dreams of, offering glorious flowers in every shade except blue. A long season of bloom (though individual flowers last but a day), and a robust disposition makes them easy to transplant, easy to maintain, quick to multiply, and resistant to pests. Planted together in large numbers, they quickly crowd out weeds and make a carefree and colorful ground cover. You'll be surprised where they can grow and just how hardy they are!