In this study, we examined the inter- and intra-specific variation of hydraulic traits of three conifers of the Northern Rockies:Pinus ponderosa, Picea engelmannii, and Pseudotsuga menziesiito understand the mechanisms that allow different plant species to co-exist across a watershed. We quantified differences in plant xylem water potential (ψx), xylem tissue vulnerability to cavitation (P50, or ψ causing 50% loss of hydraulic conductivity), and safety margins for co-occurring trees from low and high elevations. We then investigated xylem vulnerability to cavitation with rooting depth. We found that xylem vulnerability to cavitation did not correspond to where tree species were found in the landscape. For example,P. ponderosagrew in more xeric locations, whileP. engelmannii were largely confined to more mesic locations, yet P. engelmanniihad more negative P50values.P. menziesiihad the lowest P50value, but displayed little variation in vulnerability to cavitation across the hydroclimatic gradient. These patterns were also reflected in the safety margins;P. menziesiihad the widest safety margin,P. engelmanniiwas intermediate, andP. ponderosadisplayed the narrowest safety margin. All three species were also using water sources deeper than 30cm in depth, allowing them to persist throughout the mid-summer drought. Overall, species-specific hydraulic traits did not necessarily follow a predictable response to the environment; instead, a combination of physiological and morphological traits likely allow trees to persist across a broader hydroclimatic gradient than would be otherwise expected from hydraulic trait measurements alone.