Lensless imaging has recently become an alternative and cost-effective choice for many macro and micro applications, like wave-front sensing, fluorescence imaging, holographic microscopy, and so on. However, the polarized imaging, especially the cross-polarized light, has rarely been explored and integrated in lensless imaging methods. In this paper, we introduce the cross-polarized illumination into the lensless system for high-contrast and background-free imaging of plant samples. We capture a snapshot measurement and apply the blind deconvolution for reconstruction, obtaining the depolarized imaging of plant samples. Experiments exhibit the specific and sparse structures of the root system and vessel distribution of samples. We also build a corresponding lens-based system for performance comparison. This proposed lensless system is believed to have the potential in studies on the root development and water transport mechanism of plants in the future.