This paper is a wide-ranging reflection upon landscape architectures highest ambition to serve as the agent of large-scale landscape stewardship leading to an ideal state of sustainability.Stewardship, as conceived by Ian McHarg, is critically examined, with discussion of how nature and ecology are constructed in McHargs worldview and how this legacy continues to inform landscape architectural discourse.Reactions to McHargs planning methodology are summarized with particular emphasis on the lineage of thought emerging from the University of Pennsylvanias School of Design.Part two of the paper relates the theory of stewardship to the current global crisis of biodiversity depletion and describes research directions being undertaken at Penns new Centre for Global Landscape Futures to involve landscape architectural planning and design intelligence in the future of the worlds biodiversity hotspots.The paper argues that stewardship is landscape architectures most important aspiration and most compelling raison d(e)tre but that renewed intellectual and practical efforts have to be made to authenticate its meaning.