AbstractMost fluvial vegetation canopies embody some degree of structural flexibility, resulting in hydroelastic phenomena linking plant deformation and fluid flow. Quantification of such coupled fluid‐structure motion is critical in investigating key fluvial processes. The present work presents an experimental protocol that enables such quantification. High‐speed particle image velocimetry data of unidirectional flow surrounding idealized, submerged canopy elements, consisting of polyurethane rubber models, together with the corresponding solid displacement field, were simultaneously obtained by combining fluorescent imaging and refractive index matching. The operating principle of the approach employed herein involves seeding the two phases with different tracers, facilitating independent interrogation of the dynamics of each. Time‐resolved data allowed for observation of the dynamic link between a deformable object and the surrounding flow field.