Despite an academic shift from dualistic to hybrid frameworks of culture/nature relations, separationist paradigms of environmental management have great resilience and vernacular appeal. The conditions under which they are reinforced, maintained or ruptured need more detailed attention because of the urgent environmental challenges of a humanly transformed earth. We draw on research in 265 Australian backyard gardens, focusing on two themes where conceptual and material bounding practices intertwine; spatial boundary-making and native plants. We trace the resilience of separationist approaches in the Australian context to the overlay of indigeneity/ non-indigeneity atop other dualisms, and their rupture to situations of close everyday engagement between people, plants, water and birds. Our ethnographic methods show that gardens are places where both attitudes and practices can change in the process of such engagements. In a world where questions of sustainability are increasingly driven by cities and their residents, these chains of agency help identify areas of hope and transformative potential as well as concern.