Where I live, the biggest source of blight is elderly residents who are getting too old and frail to properly maintain their yards.

There's no HOA, so the only thing you can do about it is help them. There's no option for bossing the geezers around. And I'm okay with that.

If your home value can be ruined by a little bit of yard neglect, the problem isn't the neighbor's yard. It's a neighborhood designed on such a brittle basis that the yard becomes a problem.