<p>This paper discusses the short- and long-term durability of biopolymer-treated coarse-grained soils. Despite their promise as an environmentally friendly alternative to traditional methods, the durability of biopolymer-treated soils has been a limiting factor in their widespread adoption. Therefore, we consider the durability of biopolymer-treated soils at two different stages after treatment: For short-term durability, the biopolymer gel is present in the pore structure of the soil, improving it through its finite yield stress and viscosity. In this case, our work focuses on assessing the durability against cyclic drying and wetting. The results show that, due to the pore-clogging effect of the biopolymer, rapid moisture variations and the majority of biological degradation are concentrated in a thin outer crust. Long-term durability is studied in terms of the synergistic effects of biopolymer and plant roots on soil shear strength. Biopolymer increased root diameter and, in the early stages, decreased total root length.</p> Graphical abstract <p></p>