Mishnah/Seder Moed/Tractate Sukkah/Chapter 1/5
Bundles of straw, bundles of wood and bundles of cane:
One may not use them for s'chah while they are bound together. But once he untied them, all of these bundles are valid for s'chah. And all of these (the items mentioned in our chapter as being invalid for s'chah) are valid for use as walls.