In cities across Australia and elsewhere, individuals and groups are experimenting with initiatives to link urban dwellers to local ecologies and strengthen the relation with and awareness of the environment. Community and street gardens, bush regeneration working bees, botanical and bird-watching expeditions in city parks and green areas are examples of this renewed interest in urban ecologies. What role can we, as design researchers, play in connecting city people to the ecologies they encounter in their everyday lives? This paper discusses a project in an urban precinct in Sydney. We made three campaigning artefacts: a library installation, seed balls made with kangaroo grass (Themeda triandra), and a map tracing a planty route around our urban university campus. Design experiences like workshops and walkshops mobilized these campaigning artefacts. This paper focuses on the seed balls to offer an example of how plants can decenter humans in the design process. We consider plants as possible allies in design activism and advance the idea of “planty design activism.” Global climate breakdown presented the plants and us with the challenge of Australia’s hottest year on record. The findings, drawn out through ethnographies and a participant survey, show that interactions with plants can amplify people’s connection to the environment and that such attachment can make the perception of climate change more present in the city.