Annual regeneration and sustainability of perennial grass populations rely heavily on the belowground population of meristems (the bud bank), yet the dynamics, morphology, and population sizes of grass bud banks have not been explored. Since the two major photosynthetic guilds of grasses vary in their aboveground phenology, their belowground bud bank phenology would likely vary as well. Therefore, the bud banks of Dichanthelium oligosanthes, a representative C₃ grass, and Andropogon gerardii, a representative C₄ grass, were examined in tallgrass prairie throughout an entire annual cycle. A. gerardii was synchronous in its bud bank development and maintained buds from multiple yearly cohorts. The bud bank of D. oligosanthes was asynchronous in its development and was comprised of a single bud cohort since it conducted a complete turnover of its bud bank during late June. The interspecific differences in bud bank development and age distribution were likely due to differences in bud longevity, quality, and control of dormancy. These differences in individual bud characteristics may reflect different roles of buds in the demography of each species. Although both A. gerardii and D. oligosanthes are inactive over the winter season, D. oligosanthes reduces its activity during the peak temperatures of summer due to its C₃ photosynthetic pathway. D. oligosanthes, which tillers in the fall, uses buds to survive over this short summer dormancy period and juvenile tillers to survive over the longer winter dormancy period. In contrast, A. gerardii uses its buds to overwinter. Thus, the bud bank characteristics of each species were determined by the bud’s role in the life history of the plant. Knowledge of bud bank dynamics, as it offers insight into the control of grass regeneration and ultimately regulation of ANPP, will be useful in understanding the underlying mechanism by which management practices and global change can alter perennial grasslands.