* Ecosystem restoration is an important tool for mitigating biodiversity loss and recovering critical ecosystem services to humanity, but restoration rarely takes into account the evolutionary attributes of the community being restored. Phylogenetic diversity (PD) represents a potentially valuable measure of restoration success because it can correlate with functional trait diversity that drives ecosystem function. However, PD patterns in restored communities are rarely assessed. * We surveyed plant communities in restored tallgrass prairies 2–19 years old and calculated two PD measures, SESMNTD and SESMPD, of the communities and seed mixture applied to sites. We also identified high-threat exotic species present in each site to determine whether PD of the seed mixture applied was related to resistance against the invasion. * We show that PD in North American tallgrass prairie restorations, as measured by both SESMNTD and SESMPD, is maintained over time even as richness declines. Neither the resulting community PD nor invasion by high-threat exotic species was affected by PD of the seed mixture used in site restoration. Thus, simply maximizing PD of seed mixtures without considering the particular component species is unlikely to help achieve restoration goals. * Synthesis and applications. These results suggest that species losses over time are not biased towards species with or without close relatives in the community. If phylogenetic diversity (PD) reflects functional trait diversity in communities, then local declines in species richness may not necessarily mean the loss of ecosystem function in restoration projects. However, PD of restored communities may be limited by low establishment rates for most species. Conservation practitioners should consider PD with careful planning to maintain overall community diversity and potentially maximize ecosystem function and services in restorations. This perspective will require a deeper understanding of the relationships between phylogenetic relatedness and traits associated with competition and fitness.