Independent instances of divergence with similar phenotypic outcomes provide natural evolutionary replicates to investigate adaptation to new ecological niches. The plant Heliosperma pusillum forms montane and alpine ecotypes that maintain different phenotypes when grown under the same conditions for multiple generations and show a home-site fitness advantage in reciprocal transplantations. Noteworthy, the montane ecotype diverged from the alpine populations multiple times independently in different geographic areas. Ovidiu and colleagues exploit this system to provide insights into the repeatability of functional differentiation in natural evolutionary replicates. They show that phenotypic convergence often has a redundant, polygenic basis, evolving via different gene expression and regulatory changes, and involves the repeated evolution of increased gene expression plasticity mediated by stable (epi-)genetic regulatory mechanisms.