I have a weed growing in parts of my yard that grows really fast and tends to take over unmown patches if I'm not attentive. My house in central North Carolina came with a wildflower garden that this stuff has come to dominate. In the winter it turns brown and dies back. It doesn't flower, and the leaves are on the soft, flexible side and not prickly at all. Very uniform green color.
The picture below is actually a still from a short video I took. At the time I thought that would give a better sense of depth. I took this in October and have only gotten around to asking the question now (sorry about that), so I can't take a better picture right now since it's all withered and brown.
Update: I have added a clearer picture. I noticed that my video starts with a clearer shot, so I captured that and added it. It's smaller since I didn't want to include the "play" button in the middle.