Aims The impact of plant age on morphological traits, peak pullout force of the root system, tensile force, tensile strength, and elastic modulus of a single root was investigated with regard to soil-root reinforcement and the interplay between vegetation and stream processes.Methods In situ vertical pullout tests, digging tests, and tensile tests were conducted across different plant ages to examine variations in plant morphological traits, root system peak pullout force, and the tensile force, tensile strength, and elastic modulus of individual roots.Results Results indicated that as vegetation grew, both the morphological traits of plants and the peak pullout force of the root system increased. However, the correlation between peak pullout force and morphological traits was not statistically significant (p > 0.05) at certain plant ages. Additionally, for roots with the same diameter, tensile force, tensile strength, and elastic modulus saw an increase with plant age, particularly in fine roots. Soil moisture content did not significantly affect the peak pullout force.Conclusions This paper emphasizes the significance of considering seasonal fluctuations in morphological traits and plant peak pullout force, as well as the biomechanical properties of individual roots. The findings are significant for enhancing soil reinforcement models by roots and comprehending uprooting mechanisms in riparian vegetation.