Using the “mushroom” metaphor for AI tool sprawl, this article argues that higher-ed leaders should stop reacting to one-off AI requests and instead treat AI as an institutional ecosystem that must be intentionally cultivated. It outlines a practical stewardship playbook—inventorying usage, building participatory governance and AI literacy, applying frameworks like RACI/TRiSM, developing ModelOps capacity, and prioritizing culture and augmentation over control—to enable sustainable, aligned adoption.