<p>Dispersion of particles in aquatic canopies is affected by physical interactions between the flow and vegetation. This study is concerned with the effect of the spatial distribution of flexible stems on the lateral scattering of tracers in aquatic canopies. Laboratory experiments were carried out with three models of stem arrangements: staggered, random, and in-line. The Reynolds number at the stem diameter scale ranged between 120 and 690, with vegetation densities tested at 1% and 1.44%. Stem vibration was measured at different locations in the model canopies, and dye experiments were conducted to quantify lateral dispersion. In particular, the effects of stem flexibility and stem resonance on stem vibration and lateral dispersion were investigated. Image processing techniques were used to measure stem displacement and plume width to calculate stem vibration and lateral dispersion, respectively. The results show that, under the specified canopy and flow conditions, staggered arrangement had the largest lateral dispersion coefficient, followed by random and then in-line distribution. We also observed variation in stem vibration amplitude along the canopy in the experiments although the vibration frequency remained the same for different stems. The results indicate that the dispersion coefficient increases with Reynolds number and canopy density. Notably, this study demonstrates that resonance-driven amplification of stem vibrations enhances the lateral dispersion and provides insights about the effects of different stem arrangements, densities, and Reynolds numbers on lateral dispersion.</p> Graphical Abstract <p></p>