Spatial genetic structure of Arundinaria appalachiana (hill cane), an upland bamboo species endemic to the southern Appalachian Mountains, USA

Premise Long‐lived clonal plants that rarely or never reproduce sexually raise important questions about persistence, genetic diversity, and extinction risk. Arundinaria appalachiana , an upland bamboo endemic to the southern Appalachian Mountains, has never been observed to flower. We investigated the spatial genetic structure and demography of this species to assess how it persists and to inform its conservation status. Methods We used genotype‐by‐sequencing of microsatellite loci to characterize clonal structure in two populations separated by 19 km on the southern Cumberland Plateau in Tennessee, USA. Rhizome networks were mapped over 8 yr to estimate rates of clonal expansion and infer genet age. Ramet density was monitored annually to detect demographic changes. Results Both populations were dominated by a few large, ancient genets; the largest covered >30 ha and was estimated to be >1700 yr old. Clonal diversity was low, and no flowering was observed during the 9 yr study. Rhizome mapping showed slow expansion (0.12–0.30 m yr −1 ) and local fragmentation. Ramet density declined significantly in one population, while remaining stable in the other. Conclusions Arundinaria appalachiana persists through clonal growth alone, forming extensive, ancient genets in the absence of sexual reproduction. This clonal longevity enables persistence, but the lack of genetic renewal raises concerns about long‐term viability in changing environments. Our findings highlight the importance of understanding spatial genetic structure in clonal plant populations and its consequences for conservation planning.