This 3 year meso-scale greenhouse study used 55 gallon columns to evaluate the survival and growth of boreal upland and wetland communities on thickened tailings (TT) with 0 cm, 10 cm, and 30 cm peat mineral mix (PMM) reclamation cap. While survival was high in all treatments, the PMM cap treatments showed significant improvement in overall plant growth, cover, and above-ground biomass compared to the uncapped treatment, with growth on the 30 cm PMM cap outperforming the 10 cm PMM cap. The plant growth response was similar between the two communities and the top performing species, in terms of survival and growth, in capped TT were Cornus sericea, Populus tremuloides, Salix bebbiana, and Scirpus microcarpus.