Societal Impact Statement Socio‐ecological crises such as biodiversity loss, climate change, and food insecurity require academic expertise and also the inclusion of diverse actors outside of academia such as farmers, policymakers, and local communities. This article develops a synthesizing account of “transdisciplinary plant sciences” that aim to co‐create research and interventions with diverse non‐academic actors. The increasing importance of transdisciplinary methods reflects their potential in fostering more sustainable relations among plants, people, and the planet. At the same time, a more focused debate about transdisciplinarity in the plant sciences is necessary to tackle its many methodological and institutional challenges in contexts of expert‐driven research and technocratic governance cultures. Summary This review article develops a synthesizing account of transdisciplinary plant sciences that include diverse non‐academic actors such as farmers, policymakers, and local communities. Five hotspots of transdisciplinarity in the plant sciences—ethnobotany, participatory plant breeding, integrated pest management, convivial conservation, and Do‐it‐Yourself “DIY” biology—are introduced to assess commonalities and differences from a comparative perspective. Across these five fields, the review reveals common opportunities and challenges of transdisciplinary plant sciences. Plant knowledge was never an exclusively academic affair, and the plant sciences can therefore mobilize rich traditions of co‐creation for more inclusive research practices. However, local plant knowledge often becomes sidelined in expert‐driven research and technocratic governance cultures that reflect serious methodological and institutional challenges of transdisciplinary approaches. A transformative agenda is needed to realize transdisciplinary promises of epistemically more robust and socially more just research. The rise of transdisciplinary plant sciences therefore raises foundational questions about the roles of plant sciences in times of planetary crises and about their potential in shaping relations among plants, people, and the planet.