Yes, I don't see why not. I imagine that lots of people would like to get involved in such a project, and if they did, it would bring the local community together as they could work together. Sometimes, these spaces get a bit rundown as the local government either does not maintain them or doesn't have the money to spend on them, and this is where the local people could help. As everyone uses parks or gardens, then everyone making sure they are in good condition makes sense. It doesn't have to be labor-intensive either, just picking up litter would be a good start.