Environmental water can help mitigate the effects of river regulation and landscape modification on floodplain vegetation; however, intrinsic variability in vegetation responses to flow makes monitoring program design and evaluation challenging. We used 10 years of monitoring data from the Lachlan River floodplains in the Murray-Darling Basin, spanning periods of severe drought and successive flood events, to explore floodplain vegetation responses. We assessed how vegetation cover at the water plant functional group (WPFG) level responds: (i) to water depth; (ii) to increasing time since drawdown; (iii) over periods of drought or regular flooding, and; (iv) to environmental water provision during drought. With increasing water depth, terrestrial groups declined linearly, while responses varied between the amphibious tolerators and the amphibious responder groups. With increasing time since drawdown, most WPFGs declined, with two amphibious groups reaching near-zero cover within a year; while the amphibious tolerator emergent group maintained low cover up to around three years post-drawdown. Under severe drought, cover of all groups declined, even terrestrial species. However, sites that received environmental water during the drought responded with higher cover to a series of flood events that occurred in the post-drought period than sites that did not, especially among amphibious groups. Our findings demonstrate that environmental water pulses during dry years facilitated the recovery of floodplain vegetation following extreme drought. The estimated WPFG cover values in response to flood, drawdown, and environmental water provide indicators for expected outcomes, monitoring design, and evaluation of environmental water programs for dryland river floodplain vegetation. Our findings can help inform environmental water management approaches for floodplain vegetation to address challenges around droughts, climate extremes and reduced water availabilities.