The progressive increase in the industrialisation, consequently the energy consumption and carbon footprint reacquaint the sustainable and environmental credentials of hydrated lime mortars and re-congregate the implications of such binders in masonry construction. The low water retaining characteristics of hydrated lime mortars that often results in insufficient bond development with the subsequent substrate, were manipulated through the incorporation of powdered Jacaranda seed pods and silica fume to establish mortar-masonry optimisation in practice. Although there are numerous studies addressing the agricultural waste incorporation in cement-based materials, the incorporation of Jacaranda seed pods on construction materials have not been reported in the literature. Characterisation study comprising the elemental composition and physical properties of Jacaranda seed pods were essential in assessing the compatibility of pods utilisation in hydrated lime mortars. The paper reports authentic experimental research results on the utilisation of Jacaranda seed pods as a binder substitute in hydrated lime mortars concerning the effect of dewatering on the long-term engineering properties and sustainability indices. The utilisation of powdered Jacaranda seed pods and silica fume demonstrated the eligibility of manipulating the strong water retaining characteristics of hydrated lime mortars to attain improved mortar-substrate optimisation in masonry construction. It is essentially shown in the paper that the degree of dewatering, governed by the incorporation of powdered Jacaranda seed pods and silica fume herein, could not be underestimated as this phenomenon yields approximately 18% increase in the compressive strength of hydrated lime mortars comprising both at short- and long-terms. Although the incorporation of both the powdered Jacaranda seed pods and silica fume decreased the water penetration depth and porosity of mortars by ~11% and 17% respectively, dewatering, an inevitable incident that occurs as soon as the freshly mixed mortars are placed on dry absorbent substrates, further yields a greater decrease in these physical measurements at 1 year. Incorporation of powdered Jacaranda seed pods and silica fume generated a crucial improvement on cost efficiency and eco-strength efficiency of mortars both at 91 days and 1 year. The results have shown that more than 30% reduction on the carbon footprint could be established through this practice. It is essentially established in the paper that the degree of dewatering, experienced at freshly-mixed stage, determines the authentic performance of hydrated lime mortars in masonry construction and governs the veritable sustainability analysis to be performed. The results reported in this paper does not only encourage the re-introduction of the hydrated lime binder in construction practice but also assert a cleaner alternative waste management route for the agricultural wastes.