Crassula nemorosa is widely distributed in the southern parts of South Africa, in the Eastern Cape, Western Cape and Northern Cape provinces, and in southern Namibia. It occurs from the Baviaanskloof to Queenstown, in the escarpment mountains of the southern Great Karoo, in the Robertson Karoo and northwards to the Richtersveld and Hunsberg, mostly associated with rock crevices growing on shady southern aspects of cliffs and shady boulders from about 200–1 800m, mainly sedimentary, sandstone, shale or dolomite. Plants grow in shallow soil on rocky ledges, and can form large groups filling up the crevice. Temperatures are hot in summer and warm to mild and cold in winter. The average daily maximum temperature is 22–24°C and daily minimum 9–14°C. Rainfall occurs mainly in summer (thunder showers) in the eastern part of its range, with winter rainfall in the Western Cape and Namaqualand (cyclonic), ranging from 200–450 mm per annum. In spite of the rainfall, the plant retains its winter-growing habit. The associated vegetation consists of the Albany Thicket, Nama-Karoo and Succulent Karoo Biomes (Mucina et al. 2006).

At Danielshoek, between Cradock and Pearston, plants were recorded on a shale cliff face (Beaufort shale, Adelaide Subgroup, Karoo Supergroup). The associated cliff dwellers here are Crassula lanceolata subsp. lanceolata, Crassula lanuginosa var. lanuginosa, Delosperma sp., Drimia uniflora and Haemanthus albiflos. At Meiringspoort plants were observed occupying small crevices in solitary stands.

Fig. 4. Crassula nemorosa in flower on a quarzitic sandstone cliff at Meiringspoort in the Western Cape. Note the variability in leaf shape.

On the Baviaanskloof in the east, plants grow in deep, shady, mineral-poor, quartzitic sandstone kloofs (Cape Supergroup) in Gamtoos Thicket, growing from Gert Smitskloof to the Witterivier in the east. The habitat sometimes fringes on fynbos and Afromontane forest along the lower mountain slopes. At Gertsmitskloof, Crassula nemorosa shares its habitat with other cliff-dwelling Crassula lactea, Crassula perfoliata var. minor, Crassula perforata, Delosperma esterhusyseniae, Gasteria rawlinsonii, Drimia anomala, Plectranthus verticillatus and Albuca bracteata (= Ornithogalum longibracteatum). Along the Witterrivier plants grow among moss on shady cliffs.

Fig. 5. Crassula nemorosa growing in Gert Smitskloof, Baviaanskloof, Eastern Cape, sharing its habitat with Gasteria rawlinsonii.

At Badspoort near Calitzdorp plants grow in quarzitic sandstone crevices usually in solitary stands and occasionally shares its habitat with Adromischus triflorus. At Droeriviersberg between Worcester and Robertson  the plants also grow in mineral-poor quartzitic sandsone soils, occurring as solitary stands filling the rock crevices on south-facing aspects in Robertson Karoo (Succulent Karoo Biome). At Koeries in Bushmanland (Northern Cape) near Aggeneys (Desert vegetation) plants grows in a hard metamorphic gneiss crevices and quartz also in solitary stands sharing its habitat with a species of Oxalis. At Kosies in the Richtersveld (Northern Cape) the plants grow in quarzitic rocks in Succulent Karoo Vegetation.Plants were also photographed on Konsertienaberg, Hunsberg, southern Namibia.

Fig. 6. Crassula nemorosa in flower at Koeriesberg, Bushmanland, Northern Cape. Plants here grow on quarzitic soil and the plants are smaller and less developed (depauperate) due to the dry conditions