Lime mortar is the traditional mortar used during the olden days for building purposes due to its greater strength and its resistance to water and other impurities from the atmosphere. Due to its lower elasticity nature and spreading area, it is not preferred nowadays. But, it is preferred for restoring the historical monuments and places due to its strength and resistance. Hence, to improve its performance better, various additive agents were added to it. To reduce the cost and also to increase the strength, natural polymers were used. Likewise, in this, the natural polymer Prosopsis julifora (PJF) improves the mortar's quality. The PJF is rich in carbohydrates and natural water retention capacity. Due to this, the carbonation process and elasticity of the mortar are increased. The PJF extract is mixed in 1, 3, and 5% with lime mortar to observe its efficiency in terms of consistency, strength, durability, and natural resistance to water and salt crystalline. Among these three PJF sample types and reference sample-based mortar, the PJF-5% shows the best result compared to the other sample in all the analyses. Therefore, PJF-5% can increase the elasticity and produce greater strength after ninety days of the hardening process.