Vegetation can be used to stabilize slopes and for erosion control along water bodies, or for improvement of soil health and biodiversity, mainly through the functionality of their roots. Plant roots exhibit a segmented and non-uniform structure, with their diameter typically decreasing as they extend deeper into soil. This study explores the impact of evaluating possible failure types in roots on the tensile strength using Salix sp. (willows). The tensile strength of roots grown in pot experiments was determined on single root specimens at 30, 60, and 90 days, respectively. The failure pattern for each measurement was categorized as breakage failure from the top third, middle third, bottom third, and slippage after each tensile test. One-way ANOVA and post hoc analyses to establish pairwise comparisons were used to evaluate these failure types with tensile strength for each given age. This evaluation suggested that all failure types recorded along the root yielded a reliable measure of tensile strength, free from underestimation or overestimation until 2 months of age. Therefore, it would be beneficial to explore tensile strength beyond the middle third considering the root morphology is non-uniform.