Haworthia monticola Fourc.
Common names: mountain haworthia (Eng.), Willowmore dwergaalwyntjie (Afr.).
Haworthia monticola is a dwarf, cluster-forming, cliff-hugging plant, with light green, linear lanceolate, succulent leaves with pale, longitudinal markings and soft spines and bears a solitary inflorescence of pinkish-white flowers in summer. It grows in mountains in various dry river valleys south of Steytlerville in the Eastern Cape. Best grown in containers.
Fig. 1. A close-up of a cluster of Haworthia monticola growing on an upper cliff face at Aasvoelberg (Eastern Cape), during the dry season; sharing its habitat with Curio citriformis, a moss and species of lichen.
Plants dwarf-sized, rosulate, prolific from base, forming dense clusters up to 80 mm in diameter and consisting of up to 24 heads. Rosettes about 20–40 mm in diameter. Roots grey, terete. Leaves ascending spreading, becoming incurved during dry periods, up to 40, linear lanceolate, 20–30 mm long, attenuate, soft, with soft spines on margins and keel. The surface lineate (5 parallel lines), somewhat translucent. The lower surface keeled, green becoming purplish during dry periods; apex mucronate. Inflorescence ascending, racemose, up to 60 mm long with about 10 flowers in distal half. Perianth tubular, curved, ascending-spreading, 10 mm long, pinkish-white with green mid-stripe. Ovary tubular, 4 × 2 mm, green; style 1 mm long, curved, capitate. Flowering is mainly in midsummer (December to January). Seeds are dispersed by wind in summer and early autumn.
Fig. 2. Haworthia monticola on a sheer cliff at Aasvoelberg during the dry season, sharing its habitat with Delosperma esterhuyseniae and Adromischus subdistichus.
Haworthia monticola is quite common and widely dispersed and consequently not threatened. The plants are also safeguarded by their difficult to reach habitat, and its distribution falls within a greater conservation region.
Fig. 3. A cluster of Haworthia monticola growing in a cliff crevice at Aasvoelberg (Eastern Cape). Note the numerous species of lichen and moss.
Distribution and habitat
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.
Derivation of name and historical aspects
Haworthia monticola plants were collected and named by Henri Fourcade (1865–1948), a forester from Knysna who became interested in indigenous plants. He collected his specimens near Uniondale and named his plant in the Transactions of the Royal Society of South Africa in 1937. The species name monticola, means ‘mountain dweller’ and pertains to its mountainous habitat.
Haworthia monticola is closest to H. vlokii, and the latter is regarded as synonymous by some botanists. It is also related to H. zantneriana but is at once distinguished by its margin with soft spines.
Fig. 6. A narrow crevice in a cliff-face on Aasvoelberg. Note how clusters of Haworthia monticola are molded or shaped by the shape of the crevice.
The leaves are flattened, becoming more spreading in shadier environments, an adaptation to maximise absorption of light. Leaves are green, becoming purplish during dry periods, reducing absorption of light and slowing down photosynthesis. They are long-lived, with soft leaves that wither from the base. The fleshy leaves are soft, becoming turgid after rain, but channelled during dry periods, an adaptation to the extremely dry habitat.
The soft, unarmed leaf texture and entire margin suggest a reduction in armament in response to the undisturbed cliff habitat, in contrast to the thorny but heavily grazed surrounding thicket vegetation. Plants within reach of herbivores, such as the rock dassie (Procavia capensis) are grazed in habitat.
The inflorescence is ascending to spreading, the white flower (corolla), attracts flying insects that accomplish cross-pollination. The capsule ripens in autumn and the seed is dispersed by wind at the time of year that coincides with autumn thunder showers as well as the upcoming winter rainfall. Seeds are small, angular and ideal for establishment in crevices. Germination occurs within 14–21 days.
Fig. 7. A cluster of Haworthia monticola in flower on an upper cliff-face on the Aasvoelberg.
Haworthia monticola suckers freely from the base, forming dense, rounded clusters. Continual sprouting from the base represents an efficient vegetative backup dispersal strategy for this harsh cliff-face environment. Detached clusters or heads will also root if they fall into a crevice.
No medicinal or cultural uses have been recorded. Haworthia monticola is grown as an ornamental pot plant and is well-established in cultivation throughout the world.
Fig. 8. A rounded cluster of Haworthia monticola on a cliff on Aasvoelberg, the leaves reddish brown a result of it being the dry season.
Growing Haworthia monticola
Because of its small size, Haworthia monticola is best grown as a pot plant. The soil should be sandy and slightly acid, the plants kept in small containers, in partial shade. Plants are easily propagated by division and grow well in cultivation. Its very easy growing nature maximises its survival rate.
Grow in dappled shade. Plants rapidly respond to watering, becoming turgid, and should be fed sparingly with an organic fertiliser throughout the year.
Sow seed in autumn, in a shallow tray in a sandy mixture e.g. a mixture of peat, sand and polystyrene, and keep moist. Germination is within 3 weeks and once large enough to handle, transfer to individual containers. Place container in a shady position but with full light. The south side of a building is ideal.
Plants are relatively disease free but aphids, slugs and snails can sometimes be a problem.
- Bayer, M.B. & Van Jaarsveld, E.J. 2001. Haworthia. In U. Eggli. (ed.), Illustrated handbook of succulent plants: monocotyledons. Springer, Berlin.
- Bayer, M.B. 1999. Haworthia revisited, a revision of the genus. Umdaus Press, Hatfield.
- Fourcade, H.C. 1932. Contributions to the Flora of Knysna and neighbouring divisions (H. monticola). Transactions of the Royal Society of South Africa 21: 78.
- Haworth, A. 1819. Supplementarum Plantarum Succulentarum. London.
- Mucina, L. & Rutherford, M.C. (eds) 2006. The vegetation of South Africa, Lesotho and Swaziland. Strelitzia 19. South African National Biodiversity Institute, Pretoria.
- Scott, C.L. 1968. A new species of Haworthia. Journal of South African Botany 34: 1.
Ernst van Jaarsveld
Kirstenbosch National Botanical Garden (Retired 2015)
Extraordinary senior lecturer and researcher,
Department of Biodiversity and Conservation, University of the Western Cape
Plant Type: Succulent
SA Distribution: Eastern Cape
Soil type: Sandy
Flowering season: Early Summer
Flower colour: Green, White
Aspect: Morning Sun (Semi Shade), Afternoon Sun (Semi Shade)
Gardening skill: Easy