Focusing on invasive plant species management issues, we propose an empirically based contribution to one of the main challenges of contemporary geography theory, that of materiality. In keeping with the aim of analysing how practitioners on the ground engage with invasive aquatic plants in the littoral lakes of Aquitaine (south-west France), we endorse a relational approach to categorisation, while advocating a still overlooked critical attention to the most vibrant trends in new materialist geography, namely, the risk of minimising the separation issue. Our results suggest that such an approach can enable research to open up to novel opportunities for operational engagement with rapidly changing environments: indeed, we discuss how participatory territorial governance mechanisms should give way to ordinary modes of relating and separating, a condition to successful implementation of everyday contextualised struggles against invasive species, far from vitalist or eradication rhetoric.