Abstract.This paper describes a simple method to estimate the root water potential of trees using the root suckers as xylemic probes. On the day before the water potentials were measured in pressure chamber, all the sucker shoots were enclosed in plastic bags to prevent transpiration. Under the premise that the potential at two points in a flow system would be equal if there were no flux between these points, the sucker shoot water potential estimates the root water potential. The results are not dependent on the sucker architecture, are consistent with the soil‐plant‐atmosphere continuum concept, and are supported by psychrometric measureme