In the present study, we examined the development of coherent motion and the wake structure behind the finite-length vegetation patch. The vegetation patch consists of an emergent rectangular array of cylinders. Three vegetation patch length (L-p) and two vegetation density (lambda) are tested. Turbulence measurements were intensively conducted in partly-vegetated open-channel flows by using PIV. The mechanisms which control the flow and turbulent development around the vegetation patch are discussed. The results indicated that an increase in the vegetation patch length causes acceleration of the turbulent development behind the patch and increases the length of wake region downstream of the patch where its effect is significant.