Unnatural water regimes of flood control reservoirs limit vegetation establishment in littoral zones and produce mudflats with low structural complexity insufficient for many juvenile fishes. One strategy to enhance habitat on mudflats is to sow cool-season plants to provide submerged structure when inundated. However, how long the structure of these plants persists following inundation has not been evaluated. To investigate the species-specific responses of cool-season plants to inundation, we submerged six cool-season plant species in outdoor flow-through tanks and monitored maximum height and density of plant structures over time. Time-to-event analyses and generalized linear models were used to characterize differences in structural persistence between species over time. Plantings degraded rapidly if inundated before plant maturity. However, mature plants of Marshall Ryegrass Lolium multiflorum and Triticale Triticosecale provided dense structure for periods long enough to provide refuge for juvenile fish. As Ryegrass degraded, stem density decreased producing wide gaps relative to Triticale which remained dense and complex. Differences in plant architecture may influence the quality of habitat and which fish species and age class utilize each planting. Our results indicate that cool-season grasses planted in mudflats can persist after inundation long enough to enhance seasonal fish habitat and differences in plant structural characteristics may allow managers more flexibility to target desirable fish species.