Mine tailings often contain high concentrations of metals that may lead to serious environmental concerns. Phytoremediation by suitable plant species, coupled with organic amendments, represents an intriguing way of improving the quality of mine tailings. We conducted a glasshouse pot study to assess the impact of biochar derived from wheat straw (BC) and wheat straw (WS) at different application rates (w/w: 0%, 1%, 2%, 5%, 10%) in enhancing physicochemical and biological attributes of iron ore mine tailings and promoting perennial ryegrass (Lolium perenne L.) growth and mediating uptake of metals (Co, Cu, Fe, Mn, Zn, Cr, Ni, Pb) and As. The pH of iron mine tailings (6.62 with 0% amendment) significantly increased pH to 8.01 in BC 10% but decreased to 5.33 in WS 10%. However, electrical conductivity, total carbon, total nitrogen and cation exchange capacity increased significantly with application of either amendment. Improvement in physicochemical parameters of tailings by amending with WS showed a significant increase in plant growth than BC amendment. Shoot accumulation of As and Pb by perennial ryegrass was low (below detection limit), whereas that of Co, Cu, Fe, Mn, Zn, Cr and Ni increased with an increase in both BC and WS application. Microbial biomass carbon and respiration were enhanced more in the WS than in BC treatments. This study suggests wheat straw behaved more efficiently than biochar for this iron ore mine tailings.