One of the few things The Walking Dead has really done right in season 4 is showing the further deterioration of the world around the prison. At the point in time when the story takes place, the walkers have been around for a while and nature is starting to encroach on the cities in small ways like vines and plants growing rapidly. Which in an environment like Georgia would happen super fast.
There were two great scenes where we saw what I’d call growers. One where we saw a real, full on grower in the woods. A camper who had died under a tree and had rotten away quite a bit. Moss was growing on him and he seemed to be becoming part of the tree and the land around him. Oddly enough I found that idea rather comforting in a way.
In another scene we see zombies emerging from, and hung up in a patchwork of vines. The level of deterioration and integration with the plants is quite different but in both cases we have zombie which have been in a place long enough for plants to grow up around them and ensnare them or become virtually inseparable from them.