Reedy Lake is a 550 ha floodplain wetland of the Barwon River estuary in Geelong, Victoria. Since 1983 the extent of reed beds, comprising Phragmites australis and Typha domingensis, has increased by 51% to now occupy 353 ha of the wetland. The conditions for this change were first created over 130 years ago with the exclusion of saline estuary water from the lower Barwon River. Subsequent changes, including increased lake storage levels and more frequent summer flooding made conditions more favourable for reeds, but the removal of cattle in the 1970s triggered the recent, rapid expansion. This paper documents the dynamics of reeds in the lake drawing on satellite NDVI analysis, historical vegetation mapping, groundwater monitoring and land use history. The relative importance of grazing, salinity, carp and water levels on reed management are discussed.