A deciduous tree growing up to 16m high which suckers freely with white or grey bark with horizontal lines that becomes rough and darker with age. Buds and young twigs are thickly white and woolly. The dark green leaves are shiny above and white or grey and woolly beneath. Greenish-yellow catkins appear in spring. It invades river banks, vleis and dongas.
Annual erect herb 0.5-1.0 m high, with flowers resembling small sunflowers. Flowers heads one to several, disc florets yellowish orange, they bloom between summers to autumn. Leaves silvery green in colour with small white hairs beneath, mostly alternate but opposite towards the base, oval to lance-shaped, 30-80mm long, margins coarsely toothed. Seeds are brown to blackish in colour, flat, winged along the margins, 3.5-5mm long.
Willow hakea is a shrub or small tree adapted to a Mediterranean climate. It is capable of surviving hot, dry summers but not restricted to these conditions. It flowers in spring and early summer (September to January) in South Africa. Infestations of this plant replace indigenous vegetation and prevent the regeneration of indigenous species.