B. australis is an herbaceous perennial that reproduces both sexually and asexually by means of its spreading rhizomes. The plant is erect and emerges from the rhizomatic network. The roots themselves are branched and deep, which helps the plant withstand periods of drought. The plant branches extensively about halfway up.

The plant may attain a height of 1 to 1.5 metres, and a width of 0.6 to 1 metre. The grey-green trifoliate leaves are arranged alternately, and are further divided into clover-like leaflets that are obovate in shape, or wider towards the apex. Flower spikes appear in early summer. Emerging at the pinnacle are short, upright terminal racemes with pea-like flowers that vary in colour from light blue to deep violet. The flowers, which bloom from spring to summer depending on the region, are bisexual and are roughly 2.5 cm (0.98 in) long.

Hardiness zones: 3-9

Seeds per packet: 10

Note: Ornamental use only. This plant and/or seeds may be poisonous.