Choice among local, non-local, and cultivar seeds for restoring native ecosystems is not purely an academic question—it also has practical consequences. In this article we summarize a series of genetic and competition studies of big bluestem (Andropogon gerardii Vitman. [Poaceae]), Indian grass (Sorghastrum nutans (L.) Nash. [Poaceae]), and purple prairie clover (Dalea purpurea Vent. [Fabaceae]) from remnant and restored Illinois (local) prairies, non-local remnant prairies, and 6 grass cultivars. We found genetic differences between local and non-local seed sources, that large populations do not necessarily have higher genetic diversity relative to small populations, and differences in plant performance could be related to seed source. Although obtaining large quantities of non-local and cultivar grass seeds may be affordable, available, and desirable given the amount of seeds required for prairie restoration, our research indicates genetic and plant performance differences between local and non-local seed sources in all 3 species. Such differences can affect both the short- and long-term success of restoration activities.