Asparagus retrofractus is a dense, scrambling shrub that grows up to 3 m in height.  The roots are fibrous, usually formed by thin, moderately branching roots growing from the stem. The stems are much-branched, slender, woody, ribbed when young, whitish to light grey and usually zigzagged. There are generally no thorns on the branches except for some recurved spines near the base. The leaves are fine, needle-like or linear, 10–30 mm long, curved and appear in dense, fluffy tufts.

Flowers are bell shaped, pale to bright yellow-green, fragrant, and appear in clusters of 2 to 7 flowers, in axils, in autumn (from March to April). Like all species of Asparagus, after flowering, attractive pale green berries that ripen to orange-red appear. 

Asparagus retrofractus may be easily confused with A. macowanii, which is an erect, deciduous, single-stemmed shrub, reaching a height of up to 1 m. It has long, smooth stems with white, short spines both hooked and straight unlike A. retrofractus which has spines that are only recurved.