Display omitted •Glue-free biocomposites produced via hot pressing of artificial shrub.•Biocomposites show excellent hydrophobicity and high stability towards strong chemical.•Cell wall collapses enhanced mechanical bonding of fibrous components.•Depolymerization and repolymerization of lignin enhanced hydrogen bonding components.•Biocomposites obtained can potentially replace the composites prepared using adhesives. There are abundant shrub species resources in the world, but their natural defects such as short growth cycle, loose material, easy cracking plus deformation, and low strength have seriously affected their scope of application. With the ever-decreasing of natural forest resources, the research on quality improvement and efficiency enhancement of small-diameter timber of artificial shrub represents a promising effort in global continual advancement. In this study, an innovative and environmentally-friendly approach was developed to produce high-quality biocomposites from Buxus sinica. Pretreatment of Buxus sinica in an alkaline sodium sulfite solution had degraded part of the amorphous structure from the cell walls. The fiber cell walls collapsed completely in further thermoforming, resulting in a closer alignment of the fiber filaments before the formation of high-strength physical and chemical bonding, expanded crystalline regions, and enhanced dimensional stability. The resulted biocomposites show higher ultimate tensile strength (5.31 times) and ultimate flexural strength (5.22 times) than that of Buxus sinica. In addition, the preparation method also endows the biocomposites with excellent hydrophobicity and high chemical stability towards concentrated strong acid and alkali. Overall, this study reveals a promising method to effectively transform the artificial shrub resources into high-quality biocomposites with versatile applications.