The paper explores the activities of three Los Angeles artists and activists, Lewis MacAdams, Lauren Bon and Jennifer Price, who suggest a shift from the paradigm of a distinction between civilisation and nature in US culture, to a more holistic form. The object that materialises this hybrid state in their work is the Los Angeles River. They aim at bringing it back into the city's self-image as a socionatural object. What are the political implications of the artistic reinvention of nature in the cities? The cultural studies approach allows the use of the methodological and theoretical tools of both ecocriticism and political ecology. MacAdams has focused on reinvention; the works of Bon and Price are focused on memory and access, also raising the question of environmental justice. This paper provides examples that contribute to the growing field of research in the humanities and social sciences on urban nature.