At the beginning of the twentieth century, the Dutch botanist Hugo de Vries published an entirely new theory of evolution, the Mutation Theory, which claimed to overcome what were perceived as major problems with conventional Darwinian evolution. Today, historians and biologists alike tend to dismiss mutation theory as little more than an obstacle on the path to the modern evolutionary synthesis, but during the early decades of the century the USA in particular witnessed intense interest in the theory and its significance, among both scientists and laypeople. The theory was widely discussed in print, everywhere from scientific journals to popular newspapers and magazines. This reporting centered on the species of evening primrose (Oenothera Lamarckiana) that had provided the bulk of the experimental evidence for the theory. The flower and the theory became a focus for a wide range of imaginative hopes, which were often linked by a distinctively American utopianism, a drive to find a rapid, technological solution for social, political and economic problems. Americans’ diverse reactions were linked by the plant’s imagined possibilities, but the language in which these possibilities were communicated to the public also helped frame the terms in which the biologists came to express their scientific goals. And so, this paper will argue, the evening primrose helped shape both twentieth-century understandings of biology and the ways in which biology would shape the public sphere, by establishing the terms for key political and economic debates.