I thought that these would barely last the show, but they've been dropped, thrown around, stacked in corners and generally abused and other than a few tears and rough spots they are still in remarkably good condition. For foliage we had some Christmas tree branches that we just ziptied on. You could use any foliage you want. With brown ties they aren't too noticeable.
And there you have it. Easy, crafty, and without too much expense.