This paper adopts the concept of `environmental imaginaries' to explore the influence of environmental discourses upon supporters of Australian environmental movements. Rather than investigate knowledge, values, attitudes or behaviour, as is often the focus of research into public environmentalism, this study analyses the presence, absence, influence and interactions of different environmental discourses at the interpersonal scale. The relative acceptability and familiarity of different environmental philosophies, with their radically different approaches to nature, has important impacts upon the political strategies, actions and directions adopted by environmental movements. Through conducting a series of ongoing discussion groups with self-identifying `environmentalists' it is found that nature is constructed predominantly through the language and concepts of sustainable development, although this discourse coexists with a number of concurrent and oppositional viewpoints. The power of sustainable development is self-sustained through the normalisation of particular languages and modes of expression. Alternative ideas and discourses are inhibited by a lack of language and familiarity and consequently disempowered and relegated to subordinate positions within discussions. The paper concludes by arguing that the lack of acceptance of alternative ecocentric ideas within the environmental community risks de-radicalising the movement and limits the diversity of political strategies and options that it could potentially adopt.