<p>Coastal vegetation serves as a resilient, economically viable, and environmentally sustainable approach to mitigating tsunami impacts. This study examines its effectiveness using a three-layer model of <i>Pandanus odoratissimus</i>, tested in a glass-sided flume with a 1:30 undistorted Froude scale. Vegetation characteristics, based on field surveys, were arranged in staggered patterns with varying lengths and layer combinations. Both rigid and flexible models were used to assess the impact of vegetation rigidity on hydro-elastic interactions. Hydrodynamic forces were measured on a simplified square building model using a three-axis load cell. Bore-type waves simulated tsunami-like conditions, validated against real tsunami data. Results show that vegetation significantly reduces bore height and hydrodynamic forces compared to the bare case. The effectiveness of vegetation depends on the tsunami intensity, vegetation structure, mechanical properties, and spatial extent. Layered vegetation configurations enhance wave attenuation by introducing vertical heterogeneity, with roots resisting near-bed flow, trunks interrupting mid-depth currents, and crowns interacting with surface flow. Rigid vegetation outperforms flexible vegetation in longer configurations due to its persistent structural resistance, while flexible vegetation is more effective at shorter lengths due to its capability to deform and dissipate energy rapidly. The findings highlight the importance of designing effective vegetation-based coastal defenses considering the vegetation structure, mechanical properties, and spatial extent to mitigate tsunami forces on buildings.</p>