It is a prostrate, low shrub with pendulous yellow, green, red or nearly black pea-flowers from spring to summer.

Gastrolobium sericeum is a low growing, dense prostrate or twining shrub to 1 m (3 ft 3 in) high.

The leaves are arranged alternately on the stem, elliptic to orb-shaped sometimes oval, 6–50 mm (0.24–1.97 in) long, 6–30 mm (0.24–1.18 in) wide, prominently veined, wavy, margins finely scalloped and rolled under, apex rounded to sharp or occasionally notched.

The pendulous yellow, green, red or nearly black pea-flowers have yellowish or green markings, the standard petal 15 mm (0.59 in) long, the keel 12–16 mm (0.47–0.63 in) long and smooth.

[2][3] Gastrolobium sericeum was first formally described in 1864 by botanist James Edward Smith and the description published in Transactions of the Linnean Society of London .