Big sagebrush (Artemisia tridentata) is a widespread and locally dominant shrub throughout many ecosystems in western North America. Based mainly on differences in microsite occurrence and morphology, there are three broadly recognized subspecies of big sagebrush. These subspecies are found at varying elevational and soil moisture gradients and have also been found to differ in palatability, digestibility, chemical composition, and genome size. Several studies have reported subspecies-level differences in survivorship and physiology in A. tridentata, however these studies have been often limited in population sample size. More recent genecological studies have found evidence that subspecies has little to no contribution to survivorship, fecundity, and freeze resistance in big sagebrush, and suggest that cytotype and climate-of-origin may play a larger role in phenotypic variation for big sagebrush than previously thought.  To explore possible differences in ecophysiology among purported subspecies of big sagebrush, I measured morphological and physiological traits in a big sagebrush common garden to understand how genetic and environmental variables (subspecies, cytotype and climate-of-origin) contribute to phenotypic expression in this widespread, drought-adapted shrub species. Despite previous evidence of purported-subspecies driven phenotypic variation in A. tridentata and variation in survival, size, fecundity, and freeze resistance based on cytotype and climate-of-origin, this study found no strong evidence of morphological and physiological variation driven by purported subspecies, cytotype, nor climate-of-origin in mature A. tridentata when grown in a common garden. These results are important as understanding what drive phenotypic expression in big sagebrush can give better insight into how climate change may affect migration and extirpation, as well as help increase the effectiveness of restoration efforts. As a keystone species in sagebrush steppe ecosystems, this is integral to the survival of these habitats.