Seven functional traits across two groups of root orders (first- to third-order and fourth- to fifth-order roots) were measured in this study to analyze their variations along different rock-fragment-content (RFC) gradients. The objective was to explore fine-root trait plasticity and adaptive strategies of ornamental tree species in rocky mountainous environments. The results showed that: (1) With increasing RFC, the specific root surface area (SRA) and specific root length (SRL) of first- to third-order roots significantly decreased, while root diameter (RD), root tissue density (RTD), and root carbon content (RCC) significantly increased. In contrast, fourth- to fifth-order roots exhibited the opposite trend-their resource absorption capacity improved with higher gravel content. (2) Across the rock-fragment content gradient, root traits diverged along two dimensional axes: PC1 (accounting for 49.04% of total variation) represented a "collaborative" gradient (associated with RD and SRA), while PC2 (18.08% of variation) reflected a resource acquisition-conservation trade-off, linked to RTD and root nitrogen content (RNC). 1st-3rd order roots were primarily correlated with PC2, while 4th-5th order roots showed higher loadings on PC1. (3) Trait network complexity increased with RFC, characterized by stronger inter-trait correlations and connectivity in high-gravel environments. Additionally, the trait network of 1st-3rd order roots was more complex than that of 4th-5th order roots. Overall, these findings highlight divergent functional strategies: 1st-3rd order roots adopt a "do-it-yourself" resource acquisition strategy, while 4th-5th order roots favor an "outsource" strategy involving collaboration with mycorrhizal fungi. In rocky environments, functional shifts occur across root orders, and ornamental trees may gain an advantage by developing thicker lower-order roots and finer higher-order roots. These findings enhance our understanding of plant survival strategies in rocky soils and provide a theoretical basis for the sustained growth of trees in gravel-rich mountainous regions.