“Weeds – even many intrusive aliens – give something back. They green over the dereliction we have created. They move in to replace more sensitive plants that we have endangered. Their willingness to grow in the most hostile environments – a bombed city, a crack in a wall – means that they insinuate the idea of wild nature into places otherwise quite shorn of it. They are, in this sense, paradoxical. Although they follow and are dependent on human activities, their cussedness and refusal to play by our rules makes them subversive, and the very essence of wildness.”