The dark fissured bark and silver-grey foliage of mulga trees contrasts sharply against the deep red soils of Mariala National Park. This remote park conserves over 27,300ha of scarps, ranges and deeply weathered plains. Mulga vegetation dominates the park, supporting rare and threatened plants and animals.

Deep red earths in the east of the park support soft mulga Acacia aneura communities—where mulga can reach up to 10 metres in height. Hard mulga communities grow on the ranges and skeletal soils in the western part of the park, where mulga rarely grows above four metres in height. Mulga forms communities with mountain yupunyah Eucalyptus thozetiana, Dawson gum E. cambageana, poplar box E. populnea and a number of wattles Acacia spp.

Mulga, along with other wattles, improves the low-nutrient soils of Mariala by making and returning nitrogen to the soil. Species of significance include a rare Hakea, which has only been recorded in the Adavale-Cheepie area of Queensland, and bowyakka Acacia microsperma, which is not well represented in other parks.