Shrub or tree 3–10 m high, ±viscid. Branchlets willowy and arching to pendulous, commonly glabrous with longitudinal resinous bands alternating with green to brown ribs. Phyllodes narrowly linear to linear-elliptic, (4–) 5–10 cm long, 1–3.5 (–4.5) mm wide, l: w ratio = 20–70, thin, dark green to yellowish green, resinous-punctate, glabrous, but margins typically ±antrorsely puberulous, normally 3-veined per face with the central vein clearly the most prominent (the 2 flanking veins often scarcely visible); lateral veins few, obscure, occasionally anastomosing. Inflorescences simple, 2 per axil; peduncles 3–6 (–10) mm long, ±appressed-puberulous; basal bract persistent; heads globular, 4–5 mm diam., 10–17-flowered, pale lemon-yellow. Flowers 5-merous; sepals united. Pods linear, to 10 cm long, 2–4 mm wide, chartaceous, glabrous. Seeds longitudinal, oblong, 4–4.5 mm long, dull, dark brown; aril terminal.
Frequently cultivated as an ornamental for its attractive weeping habit, and has various cultivars, including dwarf or low growing forms. There are numerous cultivars recognised for this species, many of which are registered, see Brueggemeier (2010: 258–263) for descriptions and photographs of most. The cultivar Acacia verniciflua ‘Curtain Call’ is a suspected hybrid between A. cognata and A. verniciflua (see Brueggemeier 2010: 265).