Although environmentally induced variation in phenotype, or phenotypic plasticity, is ubiquitous, fundamental questions remain poorly understood. E.g.: When is plasticity adaptive? What traits show such plasticity? Does plasticity contribute to diversification? And critically: How will plasticity affect plant response in a changing climate? Research in my lab explores plant phenotypic plasticity from perspectives ranging from evolutionary theory to applications in industry. Here we assess patterns of selection on and ‘adaptive plasticity ‘ in water use traits using a multi-site, multi-species design. The work will identify the adaptive value and importance of phenotypic plasticity in water use traits in a changing climate.