This paper elucidates the philosophical origins of the conception of plants as machines and analyses the contemporary technical and ethical consequences of that thinking. First, we explain the historical relationship between the explicit animal machine thesis of Descartes and the implicit plant machine thesis of today. Our hypothesis is that, although it is rarely discussed, the plant machine thesis remains influential. We define the philosophical criteria for both a moderate and radical interpretation of the thesis. Then, assessing the compatibility of (...) current botanical knowledge with both interpretations, we find that neither withstands scrutiny. We trace how biological and agricultural sciences have historically relied upon thinking of plants as machines and how they continue to do so today through rhetoric centred on breeding, biotechnology, and production. We discuss some of the most important legal and ethical consequences of obscuring the vitality of plants. Finally, we explore less reductive and destructive ways of thinking about, and using, plants. (shrink)