The restoration and rehabilitation of damaged ecosystems has become a worldwide endeavor utilizing vast resources and ecological knowledge to build functioning and resilient ecosystems. Biodiversity restoration increases the likelihood that present species are well-adapted to the environment or can complement each other in resource use. Genetic diversity in populations may increase establishment rate, resistance to invasion, and resilience in a changing world. In parallel field and greenhouse experiments, I established colonies of the submersed aquatic macrophyte Vallisneria americana. Colony survival and performance was affected by environmental conditions in the field and genotypic diversity in the greenhouse. In the presence of nonnative Hydrilla verticillata, V. americana height was reduced; however, biomass increased, suggesting resource partitioning in response to competition. These results suggest that genotypic identity and diversity are important in early establishment of plant populations and calls attention to designing restorations that incorporate genetic information about source populations.