This mixed-method study aimed to investigate the efficacy of an intervention unit that integrates perspectives from Education for Sustainable Development (ESD) to foster plant awareness, within the context of botanical lessons for trainee science teachers. Third-year undergraduate students (n = 91) studying to become lower secondary school (grade 7–9) science teachers from a public university in East Java, Indonesia, participated in this study. Data were collected through a self-reported questionnaire, reflective journal entries, and focus group interviews. The findings revealed a statistically significant increase in the participants’ attention and attitude towards plants, relative interest in plants, and self-efficacy in teaching plant-related topics. The triangulation of the analysis results from the reflective journals and focus group interviews demonstrated that through transformative learning, the participants’ experiences, perceptions, and learning evolved throughout the intervention unit, leading to their more comprehensive understanding of plant-related issues and their connection to broader sustainability concerns. These findings imply that the integration of ESD perspectives into botanical education positively affects plant awareness. Future research could further investigate the long-term impact of integrating ESD perspectives on teacher training programs.