This paper is about leveraging cultural ways of knowing such as ethnobotany in order to increase STEM engagement in Chicanx populations. The novel Community Learning and Ecological Sustainability Paradigm (CLESP) framework utilized in this study combines social justice, Chicana feminist epistemology, land-based pedagogy, critical place-based pedagogy, pedagogical praxis, pluralism and ecological sustainability to achieve this end. Four preservice Chicana science teachers provided testimonio from their elder assignment and engaged in two focus groups in order to identify relevant themes that impact Chicana engagement in STEM. Major themes identified were challenges in bilingual education, elder knowledge as a form of pedagogy, stagnation in common science teaching practices, tensions between lived experiences and traditional science teaching, and leveraging community support. We advocate for a paradigm shift in science teacher preparation that must include cultural factors to promote Chicanx connection with STEM content. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]