To gain a deep understanding of the soil-plant-atmosphere continuum, it is crucial for land surface models to consider plant-related processes. This study focuses on the role of leaf stomatal conductance, which is central to photosynthesis and transpiration. Previous research showed that existing stomatal conductance schemes yield divergent results within a land surface model (LSM), implying a knowledge gap. We further the investigation on the performance of five representative stomatal conductance schemes using a full-fledged LSM, VIC+, and conduct a comparison study over a period of one to two years at two U.S. sites, Blodgett and Duke. Our results reveal substantial differences in modeling outcomes for stomatal conductance, leaf water potential, and leaf CO2 concentration. To gain a better understanding of the divergence among the modeling results, we examine the reasonableness of hourly output variables. Boundaries for unreasonable results are first established using published data for similar conditions, combined with physical reasoning, and judgements thus circumventing limitations of the lack of observational data. Based on them, large portions of the output from these schemes are deemed unreasonable. Treating these schemes as equally plausible or of the same level of credence, we present a new approach in which the stomatal conductance is estimated by simultaneously using multiple plausible expressions derived from two different schemes. This results in the introduction of an additional variable that binds two schemes into a robust one. This new scheme gives a significantly lower percentage of unreasonable variable combinations in its outputs, demonstrating its effectiveness.