Sustainability standards and certifications increasingly represent multi-billion-dollar brands that partner with corporate firms. We employ the case of South Africa's Rooibos tea industry to analyze the impacts of this shift. Examining five sustainability initiatives, our research focuses on small-scale farmers and the power dynamics shaping their involvement. The Rooibos initiatives engaged multiple approaches, but none realized sustainable outcomes. Third-party and corporate efforts exposed producers to risk and reified dependency, industry actions did not achieve intended goals, and a shared leadership project failed to address material barriers to participation. Yet examples of good practice offer insight into the types of policies needed to improve outcomes. These include shifting from a hierarchical to a relational orientation by reducing certification costs, extending support services, and ensuring inclusivity in planning and governance. We conclude by arguing that markets are a perilous tool for development. Sustainable trade systems nevertheless illustrate the promise of market-based sustainability, as these are providing marginal groups with a platform to demand more equitable arrangements.