Plants employ contrasting strategies to survive in different environments. Adaptations to environmental stress may involve investment in resistance mechanisms that enhance survivorship under stress, potentially at the cost of limiting growth. We test the hypothesis that among the American oaks that have radiated into contrasting habitats varying in water availability, some species will have greater drought resistance at the cost of reduced growth capacity. We investigate patterns of trait variation in relation to native environments in species representing lineages across the American oak phylogeny, and experimentally test the response of species to experimental water treatments. Trade-offs between drought tolerance strategies, such as solute accumulation in leaves (known to help plants regulate water potential), and growth appear in all lineages–indicating both adaptation and evolutionary constraints in physiological traits. We find that species from mesic environments have enhanced growth and resource acquisition traits when experimentally well watered. In contrast, xeric species do not have the capacity to increase growth when well watered; however they do accumulate solutes and show a greater propensity to prevent plant dieback under drought conditions. We postulate that the drought resistance traits exhibited by xeric species may require investment of resources that limits growth under mesic conditions.