Plants 30-60 cm high. Corm ball-shaped 12-16 mm in diameter, tunics grey-brown, forming a fine network or lattice, inner layer membranous and unbroken. Leaves (3)4 or 5, sometimes dry and broken at flowering time.

Stem unbranched, bearing 2-4 sheathing bract leaves, not overlapping.

Spike 2-12(-14)-flowered; outer bract 12-16(-25) mm long, inner bract shorter than outer bract and concealed, deeply forked apically. Flowers small, about 12, bilaterally symmetrical, pale pink; perianth tube with the lower part 10-12 mm long and about 1,5 mm wide; upper part horizontal and flared, 7-9 mm long, widening to about 6 mm at the mouth; tepals ball-shaped, 14-16 mm long, to 7 mm wide, curving outwards. Filaments about 7-10 mm long, anthers pale yellow, about 7 mm long. Ovary oblong, about 3 mm long; style dividing towards the tips of the anthers, arching over the filaments, branches 3-4 mm long. Flowering period: August to early October. Capsules 7-9 mm long; seeds angular-elongate, 3-3,5 mm long, 1,3 mm at the widest.

Watsonia mtamvunae is closely related to the W. densiflora complex of species from which it stands out in the few-flowered spike of small flowers, the short, non-imbricate (imbricate = overlapping like tiles) to weakly imbricate bracts, short stature and linear leaves.