The Etowah River Basin in North Georgia is a biologically diverse Southern Appalachian River system, threatened by regional population growth. This is a two-part botanical study in the Upper Etowah watershed. The primary component is a survey of vascular flora. Habitats include riparian zones, lowland forest, tributary drainages, bluffs, and uplands. A total of 662 taxa were inventoried, and seventeen reference communities were described and mapped. Small streams, remote public land, and forested private land are important for plant conservation in this watershed. In the second component, cumulative plant species richness was sampled across six floodplain sites to estimate optimal widths for riparian buffer zones. To include 90% of floodplain species in a buffer, 60-75% of the floodplain width must be protected, depending on the stream size. Soil moisture influences species richness, and is dependent on upland water sources. An optimal buffer would protect hydrologic connections between floodplains and uplands.