Nuxia congesta is a quick-growing, evergreen tree or shrub, 2-20 m high. It has a pale grey-brown to dark brown shedding bark and hairy branchlets. The leaves are hairy, dark green, slightly leathery and variable in shape and size. They are found clustered at the ends of branchlets. Coppice leaves are soft, succulent and dark green with a serrated margin. 

The flowers are small, about 5 mm long, tubular and creamy white, often tinged with mauve or purple, especially in bud. They are sweetly scented and arranged in often large congested, mushroom-shaped or flat-topped heads, at the ends of the branchlets. The fruits are small, about 3 mm long, hairy and brownish. They develop within the persistent calyx and contain fine, inconspicuous seed. Flowering time is February-November.