Peatlands are the strongest terrestrial carbon (C) sink, storing approximately 25% of the global soil C stock. In northern peatlands, Sphagnum mosses are the keystone species that create and maintain peatland functions. If the Sphagnum layer is removed or disturbed, peatlands can shift from C sinks to sources contributing to climate change. One example of industrial disturbance is Sudbury Ontario, where over a century of nickel and copper mining has contaminated the area with metal and sulphuric acid deposition, decimating vegetation. Despite reductions in air pollution starting in the 1970’s, there is no Sphagnum recolonization in most contaminated peatlands. However, recent evidence shows some localized moss recolonization, but the spatial extent and mechanisms of this growth are unknown. In order to better understand how Sphagnum is recolonizing metal contaminated peat, I targeted highly contaminated peatlands to identify the extent of moss colonies and measured colony height, area, species composition, gross and cellular morphology, and what substrates moss are growing on. Colony area was negatively associated with nickel and copper concentrations indicating that legacy metal concentrations are still affecting Sphagnum recolonization. Stem height was significantly decreased in all highly contaminated sites in all species when compared to a reference site. Results of cellular morphology indicate a positive relationship between nickel concentrations and intraspecific cell size suggesting a morphological adjustment to nickel uptake. Determining the conditions that promote recolonization will be critical for restoration efforts aimed at returning Sphagnum and peatland C storage to Sudbury’s impacted landscape.