The collards from my local CSA were perfectly flat and pliable, and easier to tear into than your average sheet of nori (the seaweed used for sushi rolls). Since they were so forgiving, cutting out the stem took mere seconds and I was able to wrap the leaves as tightly or loosely as I liked.
I have since tried these greens one more time in the cooked format, and I have to admit, for once I prefer raw. Collard greens seem milder in taste when raw, and by using some flavorful ingredients (such as the hummus) their bitterness is kept in check. See the full Recipe for Collard Green Hummus Wraps on One Frugal Foodie.