Like most other proteaceae, "B. oblongifolia" has proteoid roots—roots with dense clusters of short lateral rootlets that form a mat in the soil just below the leaf litter. These enhance solubilisation of nutrients, allowing nutrient uptake in low-nutrient soils such as the phosphorus-deficient native soils of Australia. A study of coastal heaths on Pleistocene sand dunes around the Myall Lakes found "B. oblongifolia" on slopes (wet heath) and "B. aemula" grew on ridges (dry heath), and the two species did not overlap. Manipulation of seedlings in the same study area showed that "B. oblongifolia" can grow longer roots seeking water than other wet heath species and that seedlings can establish in dry heath, but it is as yet unclear why the species does not grow in dry heath as well as wet heath. Unlike similar situations with "Banksia" species in Western Australia, the two species did not appear to impact negatively on each other.