Plant roots can provide mechanical reinforcement to the soil by increasing its tensile strength. The ability of roots to resist pull-out forces from soil is known as root tensile strength (Tr). Understanding the factors affecting tensile strength is important in evaluating the effectiveness of vegetation in soil reinforcement. The slope stabilization using grasses is an effective way to mitigate the coalmine overburden dump slope failures. This paper aims at exploring the root tensile strength of Cymbopogon citratus (Lemon grass) cultivated under six different proportions of coalmine overburden mixed cow dung. A detailed discussion has been presented on the importance of Tr for estimating the enhanced shear strength. It was observed that the root diameter is inversely associated with the Tr (MPa). Among all the six plants, the highest Tr (324.54 MPa) was found in the plant under overburden with 20% organic amendment. The species-dependent scale factors and rate of strength decay were also determined for each plant of Lemon grass. These values can be utilized in conjunction with root area ratio to determine the extent of soil reinforcement indirectly. Therefore, a deeper understanding of the mechanisms involved in root–soil interaction can contribute to the development of more effective vegetation-based soil reinforcement techniques.