Spiraea virginiana Britton is a clonal shrub with modular growth form. The species has root system and vegetative characteristics that allow it to thrive under appropriate disturbance regimes. The species probably reached optimal population numbers, genetic diversity, and widest distribution during late glacial times when frost churn and increased erosion inhibited arboreal competition. The wide range was probably achieved using sexual reproduction and small wind/water dispersed seeds. As the climate ameliorated, plants became restricted to riverine habitats. This restriction isolated and probably eliminated many genetic individuals, caused increased dependence on vegetative reproduction and restricted population numbers in a wide but discontinuous range. The riverine sites have enough erosion to inhibit arboreal competition and fragment the modular colonies, but deposition patterns suitable for the establishment of vegetative propagules. Human activities have inadvertently maintained the species in several sites by periodic clearing, but human activities are the only documented cause of extirpation.