I have also been told that when new plants are dug some of the roots are damaged so it helps to cut back on the foliage, but I was also told that once you see the first bloom and establish that what you bought is correct you should actually cut the scape out then. I have never been able to bring myself to do that and the daylilies seem to have done just fine. I can see that it might actually be best for the plant. I think most people assume that the foliage is cut back to make shipping easier, and I am sure that is part of it, but also I think the leaves are cut back to help prevent transpiration.
