Abstract Several bamboo features are responsible for its known mechanical performance and thus were applied on bionic thin-walled structures, still the particular geometry of individual vascular bundles remains unexplored mechanically. This research investigates the mechanical influence of that region in the design of thin-walled structures, comparing it with bamboo-inspired designs from the literature. X-ray microtomography was used to explore bamboo bundle's geometry, applying it as reinforcement. The proposed new design showed improvements in strength and energy absorption in axial, lateral, and flexural explicit Finite Element Analyses. The vascular bundle's geometry was revealed as an important characteristic of bamboo performance.