As the world takes a more strategic approach to the climate crisis, carbon in its various forms has become a key factor in ascertaining the sustainability of the landscape. Landscape has been recognised as a resource and mechanism for addressing the role of carbon in the environment, with literature focused on the landscape’s carbon capacity as interconnected systems of land, soil, water and organic life. It has, however, largely neglected the crucial role of the cultural, social and historical aspects of the landscape, particularly at the level of design. This paper acknowledges and explores the complexity of landscape as a natural-cultural system with the consequent difficulties this poses in legislating, calculating and measuring carbon for global, national and local targets for low/zero carbon and carbon offsetting. The discussion takes place in the arena of landscape architecture at regional/city/local scales and the life-cycle of a project including its integration into its wider social, cultural and environmental setting. This paper develops the discourse in three major areas: first, by examining how the complexity of landscape is obscured in the context of carbon-measuring tools used in landscape architecture; secondly exploring one such tool in practice to demonstrate how site-specific design decisions can impact carbon levels; and third by proposing how an integrated understanding of landscape can be built into projects to embrace complexity and operationalise low carbon visions.