To determine the growth strategies of the clonal wetland sedge Carex brevicuspis under different conditions, we measured the ramet density and biomass; numbers of total rhizomes (TR), long rhizomes (LR), and short rhizomes (SR); and environmental factors along a small-scale elevation gradient (23–26 m) in Dongting Lake wetlands, China. Ramet density and biomass were higher at low elevations as compared with those at intermediate and high elevations. There was no significant difference in the number of SR per ramet among the three elevations. However, the number of LR per ramet was higher at high and intermediate elevations as compared with that at low elevation. These results indicate that C. brevicuspis can adapt to increasing environmental stress (i.e., decreasing soil moisture contents) along an elevation gradient by producing more long rhizomes. Plasticity of the C. brevicuspis clonal growth through the modification of its meristem allocation patterns may allow for wide distribution of the species.