I only have a smallish yard in the middle of suburbia myself, so I know what you mean. As others have said, local parks are cool (go early, not many people around then!) Failing that, even a single shrub or plant behind a figure, if you get the angle right, can look like a Joe (or Cobra) in the wild. I have even used an indoor potted plant as a background in some pics, and no-one ever noticed!