Haworthia monticola grows widespread from the Boesmanspoort Mountains near Willowmore in the west, to just west of Makhanda (formerly Grahamstown) in the east. As its name implies, it is a species growing in mountains, in the northern parts of the Cape Folded Mountains adjacent to the Great Karoo to the north. It grows on cliffs at an altitude of 600–1500 m, on quarzitic sandstone (light-coloured and smooth-textured), of the Witteberg Group (Witpoort Formation, Cape Supergroup). The cliffs have many ledges, crevices and fissures, ideal for establishment of the plants.

Plants are usually confined to  south-facing cliffs, where they grow in crevices, firmly rooted and molded to the shape of the crevice. Temperature in summer is on average 25–35°C. Winters are cooler with occasional snow and frost. Rainfall occurs throughout the year, ranging from 250–400 mm per annum in the form of thunder showers or cyclonic winter rain.

Fig. 4. The sheer, south-facing cliffs of Aasvoelberg, near Willowmore, Eastern Cape, habitat of Haworthia monticola. Note the various species of lichen growing on the cliffs, this is because the Aasvoelberg is sometimes covered in cloud.

Haworthia monticola plants were observed on upper, south-facing cliffs along the Aasvoelberg (1 412 m) which is a few kilometres north west of Willowmore. The associated vegetation consists of Grootrivier Quartzite Fynbos of the Fynbos Biome (Mucina et al. 2006). Although the upper slopes and peak consist of Fynbos vegetation, it is surrounded by mainly Nama Karoo and remnants of thicket vegetation on its lower slopes and with shrubby species such as Portulacaria afra, Carissa bispinosa, Euclea undulata and Pappea capensis becoming prominent.

On the upper, south-facing cliffs there is shallow soil and limited growth space, which allows succulents to become prominent and dominant. Associated cremnophytes sharing the habitat of Haworthia monticola include: Adromischus subdistichus, Cotyledon orbiculata var. oblonga, Cotyledon woodii, Crassula biplinata, C. nemorosa, C. pellucida subsp. marginalis, C. perfoliata var. minor, C. perforata, C. rupestris subsp. rupestris, C. saxifraga and C. socialis. Other species belonging to the Aizoaceae family include: Delosperma esterhuyseniae, Esterhuysenia alpina, Lampranthus affinis and Machairophyllum albidum.

Fig. 5. Haworthia monticola sharing its habitat with Haemanthus albiflos and a seedling of Crassula rupestris and Adromischus subdistichus.