Haworthia monticola is a stemless leaf succulent that forms clumps. Its leaf rosettes become 4 cm in diameter.
The leaves are lanceolate, coloured green or red-brown according to seasonal conditions. Young erect leaves have incurving tips, old spreading ones have tips that recurve. The bulging green to dark green leaves have spines on their margins and keels. Whitish longitudinal lines are present upon the upper surfaces of the leaves, as well as small translucent (or pellucid) areas between the lines. The lower surfaces are smooth and without translucent windows, the keel not centred. A leaf becomes about 5 cm long, 5 mm wide and 2 mm thick.
The inflorescence becomes 25 cm tall, ending in a simple raceme of 6 cm, bearing about ten spirally arranged flowers of which not more than two open simultaneously. The perianth (flower) is pinkish white with green keels on its segments. Flowering happens late in summer.
The species distribution ranges from Oudtshoorn in the Little Karoo to Uniondale. The plant grows in renosterveld and fynbos.
The identity of the species is unsure, particularly regarding distinguishing it from H. zantneriana and H. angustifolia, which occur also further east. Resolving issues relating to the taxonomy of these plants will allow determination of population stability and assessment of survival threat of the plants concerned (Scott, 1985; www.redlist.sanbi.org).