Growth, below/above-ground mass ratio (BG:AG ratio), root morphology, carbohydrate content, and alcohol dehydrogenase (ADH) activity in the low-elevation species Phalaris arundinacea and the high-elevation species Miscanthus sacchariflorus buried under 0, 5, and 10 cm of sediment were investigated one, two, and three months after burial. Biomass accumulation, BG:AG ratio, and the starch content of both species generally decreased with increasing burial depth and burial time, except for higher biomass accumulation in P. arundinacea in the first month. In the first month, adventitious roots of both species, and first-order laterals of P. arundinacea, were shorter and thicker in the buried plants than in the controls. The ADH activity in both species and the soluble sugar content of P. arundinacea increased with increasing burial depth in the first month. Only the diameter of adventitious roots and the soluble sugar content of P. arundinacea were affected by burial depth after two or three months. It is concluded that P. arundinacea is more tolerant to sedimentation than M. sacchariflorus due to more efficient acclimation strategies in root morphology and soluble sugar content. However, the ability to acclimate becomes weaker over time due to consistently decreasing starch content and the trade-off between tolerance to sedimentation and plant growth.