Sophora prostrata is a kowhai native to the dry eastern side of the Southern Alps, from Marlborough to southern Canterbury. It is a slow growing native prostrate or bushy shrub with a very dense habit and tangled appearance and will grow up to 2 metres tall. The dense zigzag interlacing branches are golden coloured and the leaves very small. Leaves may be up to 2.5 cm long but usually smaller. It maintains the divaricating growth form throughout its entire life.

Its yellow flowers but smaller and fewer than in the other species of kowhai. The flowers of S. prostrata are unusual in both colour (often attaining quite orange hues, in contrast to the more typical yellows of other kowhai species) and in the manner in which flowers are borne upon the plants (they are often held in an ‘upside-down’ position, when compared with other kowhai species).