This research explores the idea of plants as designers and discusses approaches that humans can use to support plant’s productive agencies. It argues that plants have unique and valuable capabilities for creating and caring for their environments. Human interventions often overlook or constrain such capabilities. In response, the article proposes to use numerical modelling to better understand plants better while challenging the anthropocentric assumptions that are common in design. It focuses on large old trees in Tasmania as examples of outstanding (...) plant-designers that need more recognition and protection. The article also raises open questions for further research on the ethical, ecological, and aesthetic implications of vegetal design. (shrink)