This paper examines the environmental philosophy of Liberty Hyde Bailey Jr (1858-1954). A prominent agrarian and garden theorist in the United States, he naturalised culture and the human mind. Although Bailey was a plant scientist and taught at Cornell University for decades, he never fully endorsed the epistemology and metaphysics of his peers. He believed truth was provisional and he rejected spectator theories of knowledge. Bailey argued that humans were inseparable from the natural processes they hoped to understand and master. Turning away from the search for fixed truth, he celebrated contingency and the aesthetic experience of gardening. The garden was a dynamic space that blurred distinctions between nature and culture. Whereas botanists sought to classify plants and fix the meaning of the natural world, the gardener encouraged humility and an aesthetic appreciation for nature as a set of open-ended processes in which humans participated. I argue that Bailey was a 'pragmatic naturalist'. In reconciling scientific method with aesthetic experience, he provided the foundation for a new environmental philosophy in the United States. Whereas other historians have framed American environmentalism around the opposing poles of anthropocentrism and ecocentrism, I suggest Bailey provides evidence of an alternative tradition. Neither anthropocentric nor ecocentric, he believed human experience was an emergent feature of the natural world. Humans were unique, he argued, but they did not stand outside or above the environment.