Long ago in a model railroad magazine an article showed how a modeler made cat tails by using coated wire. (1) Cut the wire to the desired length for the cat tail, (2) strip off the wire coating, BUT leave a small piece of coating on one end, (3) paint the remaining small coated piece brown, the bare wire green, (4) place several of these in an area surrounded by some green ground foam. It made a believable looking little reed/marsh scene.
Steve