Wetlandscapes are low-relief complexes of wetlands dispersed among uplands. Variation in the timing, duration, and extent of wetland inundation and hydrologic connectivity influences hydrologic and habitat functions that accrue across wetlandscapes. With ongoing wetland loss and degradation, our objective was to understand differences in the redundancy of wetland plant assemblages across three Florida wetlandscapes to provide insight on how wetland loss would impact aggregate biodiversity support. Combining high frequency water stage from multiple wetlands (n = 14 to 16) in each wetlandscape with LIDAR-derived topographic maps, we created wetland hydrographs and computed inundation and connectivity metrics. We conducted vegetation surveys in each wetland twice annually (during the wet and dry seasons) for two years using two belt transects and used biodiversity measurements and multivariate ordination techniques to evaluate differences in plant diversity and the redundancy of plant assemblages among wetlandscapes. We found that the wetlandscape with the greatest hydrologic and topographic heterogeneity and rare surface water connectivity had the greatest species richness, turnover, and overall beta diversity compared to the other wetlandscapes with frequent surface water connectivity and greater hydrologic synchrony. Wetlands in the most hydrologically heterogenous wetlandscape were also situated farthest apart in ordination space based on their species composition compared to the other two wetlandscapes that exhibited reduced distance between and greater overlap among wetlands in ordination space. Combined, our results suggest that wetland elimination would most likely result in the loss of a unique assemblage in the most hydrologically diverse setting despite the wetlands here being least likely to satisfy the “indistinguishable from navigable waters” criteria for United States Clean Water Act protections. We advocate that future wetland protections across levels of governance should consider the role of hydrologic heterogeneity, including locations with low hydrologic connectivity, to maintain aggregate wetlandscape hydrologic and biodiversity functions.