1.This study compares the effectiveness of using plant species, genera, family or water plant functional group (WPFG) classifications for demonstrating differences in vegetation communities associated with inundation history. 2.Vegetation surveys were undertaken annually for 5 years from 2007–2008 to 2011–2012 at 18 floodplain wetlands. These wetlands are from two geographically separate locations situated along the lower Murray River. Wetlands have different inundation histories and have received varied amounts of environmental water since 2004. All plant species recorded were classified into WPFGs. An inundation classification was determined for each wetland at each survey time based on inundation history and inundation status at the time of survey (wet or dry). 3.This study found that plant species composition at individual wetlands is often unique with few species recorded across multiple wetlands. The use of WPFGs reduced the variability of plant communities between individual wetlands, between the two geographic locations and within inundation classifications. By reducing the variability between samples, broad trends in vegetation responses to different watering histories can be identified. 4.Individual wetlands can develop completely different suites of plant species in response to the same watering regime, particularly when separated over large distances. This variability can reduce the confidence managers have in predicting the plant communities likely to develop in response to prescribed watering regimes. Adaptively applying knowledge gained from monitoring to different wetlands or wetlands in different geographical regions is also difficult if responses are highly variable. 5.This study demonstrates that by classifying wetland vegetation into WPFGs the variability observed between samples can be reduced and the influence of floristic differences between individual wetlands and geographic locations can be negated or lessened. We discuss how the use of WPFGs can assist scientists and managers in demonstrating, predicting and communicating trends in vegetation community responses as a result of different watering regimes. The adoption and application of a consistent approach to the classification of plant species into WPFGs has the potential to enable responses and predictions to watering events to be made across broad spatial scales.