Rothmannia genus

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Rothmannia Thunb.

Family: Rubiaceae

Common names: wild gardenias, false gardenias (Eng.); wildekatjiepiering, valskatjiepiering (Afr.)

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Introduction

Wild gardenias feature solitary, widely bell-shaped, sweetly scented flowers that are creamy-white with maroon streaks or speckles.

Rothmannia capensis

Description

Description

Wild gardenias are shrubs or small trees. Leaves are opposite or occasionally in whorls of three, petiolate, elliptic, leathery, dark shiny green and hairless, except for distinct small hairy pockets (domatia) on the undersurface that cause a small swelling that is visible on the upper surface. Stipules ovate, hairy within, eventually falling. The showy flowers are solitary or appear in crowded bundles of up to 4 blooms, at the tip of stems (terminal). The corolla is widely bell-shaped, white with maroon streaks or speckles, and soft hairs in the lower portions of the throat. The 5 lobes are obovate-oblong, with cylindrical tube below and campanulate above. The fruit is globose, sometimes crowned with persistent calyx. The seeds are numerous and smooth. Flowering time is from late winter to late summer (August–February).

Rothmannia capensis in flower in Kirstenbosch NBG, showing domatia swellings on the leaves

The genus Rothmannia was named by Carl Peter Thunberg (1743–1828), known as ‘the father of Cape botany’ and a pupil of Carl Linnaeus (1707–1778), in honour of fellow Linnaeus pupil Göran Rothman (1739–1778). Rothmannia Thunb. is easily confused with Gardenia J.Ellis. The former has a campanulate (bell-shaped) corolla tube and ovate stipules, whereas the latter's corolla tube is cylindrical, and the stipules are fused together (connate).

Rothmannia capensis flower LEFT compared to Gardenia thunbergia RIGHT

Conservation Status

Status

All Rothmannia species in South Africa are Red Listed as Least Concern (LC).

Distribution and habitat

Distribution description

Rothmannia comprises ± 22 species endemic to Africa. Species diversity is concentrated primarily in tropical areas of West and East Africa. The genus occurs in moist evergreen forests, forest margins, rocky outcrops, sandy forests or near streams.

Rothmannia capensis in habitat

Currently, 4 taxa are accepted in southern Africa sensu the South African Plant Checklist (2024). South African Rothmannia species are distributed along the coastal winter-rainfall areas of the Western Cape and extend into the summer-rainfall regions in the Eastern Cape and KwaZulu-Natal. They also occur in the interior parts of the summer-rainfall provinces of Mpumalanga, Limpopo, Gauteng and North West. The genus extends into Eswatini and Botswana as well.

Ecology

Ecology

The fruits of Rothmannia species, e.g., R. capensis and R. globosa, in southern Africa are eaten directly from the tree by vervet and samango monkeys, as well as baboons, while in forest areas, bushbucks, grey duikers and bushpigs consume any fruits that fall to the ground. One can postulate that the seeds of Rothmannia species in southern Africa are dispersed by the aforementioned animals that consume their fruits. Additionally, carpenter bees frequently visit the flowers.

Fruits of Rothmannia fischeri subsp. moramballae

Uses

Use

The hard, flexible wood of the plants in this genus is popular for making instrument handles and various household utensils, including durable cooking spoons and porridge stirring sticks. The dried wood is also used for firewood. While the fruits are edible, they are not particularly tasty, however, they are traditionally used to make necklaces when dried. Historically, Mpondo men used the fruit shells as clothing. Medicinally, the powdered roots treat leprosy and rheumatism by rubbing them into small skin incisions over affected areas. The healing process of wounds and burns can be accelerated by applying the heated fruit juice. Additionally, affected areas are sometimes treated by exposure to smoke from burning roots.

Rothmannia globosa in flower

Growing Rothmannia genus

Grow

Wild gardenias are easy to grow from seed. Seeds should be removed from the ripe fruit and sown in a mixture of 3 parts river sand to 1 part compost. Keep the seed mix moist until germination, which occurs after 14 days. The plants of this genus grow moderately fast (0.7 m per year) and may flower in their second year, though most take a little longer. They are frost-resistant and to some extent drought-resistant.

The species of this genus produce attractive, sweetly scented flowers that captivate gardeners. They are suitable as specimen plants even in small gardens. They can be cultivated from seeds sown in well-drained soil enriched with compost. The plants grow very well in light shade or full sun, preferring loamy or sandy soils to clay.

Species

Rothmannia capensis

Rothmannia capensis Thunb.
Common names: Cape gardenia, common rothmannia, wild gardenia (Eng.); Kaapse katjiepiering, wildekatjiepiering (Afr.); modulatshwene (Northern Sotho); mukubudu (Tshivenda); umphazane-mkhulu (isiZulu); isithebe, umzukuza, ibolo (isiXhosa).SA Tree No: 693
Medium to tall tree, 7–15(–25) m high. Leaves opposite, occasionally in whorls of three, clustered towards the end of the branches, elliptic, 75–100 × 25–40 mm, leathery, dark shiny green, paler beneath, hairy pockets (domatia) present on the undersurface, margins entire, wavy, tip tapering or rounded, base tapering; petiole almost absent. The upper expanded part of the calyx never splitting, always bearing filiform to linear lobes; the bases somewhat widened but always clearly separated by sinuses. Flowers are widely bell-shaped, up to 80 mm long, 60 – 70 diam., white to creamy yellow with maroon streaks in the throat. Flowering time: early to late summer (December–February).
Occurs on forest margins and rocky outcrops from the Western Cape to Botswana.

Rothmannia fischeri subsp. fischeri

Rothmannia fischeri (K.Schum.) Bullock subsp. fischeri
Common name: woodland false-gardenia, scented bells (Eng.)
SA Tree No: 694
Shrub or small tree, 2–8 m high. Leaves opposite, occasionally in whorls of three, lanceolate to elliptical or broadly elliptical or narrowly obovate, 35–90 × 20–50 mm, leathery, dark shiny green, hairy pockets (domatia) present on the undersurface, apex and base tapering, margins entire, wavy; petiole up to 10 mm long. Flowers creamy with pink or purple markings in the throat, corolla tube funnel-shaped, 100 × 80 mm.
The upper expanded part of the calyx often splitting, with lobes 1–9(–18) mm long. The corolla tube is gradually funnel-shaped or has a narrow cylindrical lower half and is funnel-shaped above, 43–80 × 13–30 mm, wide at the opening; lobes 18–25 mm long.
Flowering time: spring to late summer (October–February).
Occurs in central Zimbabwe, Mozambique, KwaZulu-Natal and Limpopo provinces in semi-deciduous woodland, thickets and mixed evergreen forest patches, often on rocky hillsides or koppies, or near streams.

Rothmannia fischeri subsp. moramballae

Rothmannia fischeri (K.Schum.) Bullock subsp. moramballae (Hiern) Bridson
Common name: sand false-gardenia (Eng.)
SA Tree No: 694.1
The upper expanded part of the calyx often splitting, with short lobes 1–3 mm long. The corolla tube is narrowly cylindrical in the lower part and approximately campanulate above, 50–70 × 20–30 mm, wide at the mouth, with the cylindrical part at least half the length of the campanulate part; lobes 25–35 mm long.
Flowering time: spring to late summer (October–February), after rain.
Occurs in moist places in mixed evergreen forests, sandy forests or riverbanks in KwaZulu-Natal, Mozambique and eastern Zimbabwe.

Rothmannia globosa

Rothmannia globosa (Hochst.) Keay
Common names: September bells, bell gardenia (Eng.); klokkiesvalskatjiepiering (Afr.); umgubhe (isiXhosa); umphazane (isiZulu); thudwane (Tsivenda); sikoba (SiSwati)
SA Tree No: 695
Evergreen or briefly deciduous tree, 4–7(–12) m high. Leaves opposite, elliptic to lanceolate, 40–140 × 20–50 mm, dark green above, paler beneath, midrib and side veins yellowish to paler green tinged reddish, raised beneath, hairy pockets (domatia) present on the undersurface, margin entire, broadly tapering tip, base tapering; petiole up 10 mm long. The upper expanded part of the calyx never splitting, always bearing filiform to linear lobes; the bases somewhat widened but always clearly separated by sinuses. Flowers bell-shaped, 25 × 35 mm, creamywhite, yellowish in throat with pink speckles within. They appear singly or in clusters along short side branches, appearing in profusion, usually before the leaves.
Flowering time: winter to spring (July–November), often flowers after rain in July, and again in September.

References

  • Baloyi, K.J. 2004. Rothmannia capensis Thunb. (Rubiaceae). PlantZAfrica. Online. https://pza.sanbi.org/rothmannia-capensis.
  • Baloyi, K.J. 2005. Rothmannia globosa (Hochst.) Keay. (Rubiaceae). PlantZAfrica. Online. https://pza.sanbi.org/rothmannia-globosa.
  • Boon, R. 2010. Pooley's trees of eastern South Africa, a complete guide. Flora & Fauna Publications Trust, Durban.
  • Bridson, D.M. 1984. Notes on Rothmannia fischeri (K.Schum.) and allied species (Rubiaceae subfam. Cinchonoideae). Kew Bulletin 37: 67–72.
  • Coates Palgrave, K. 2002. Trees of southern Africa. Struik, Cape Town.
  • De Wit, T. 2022. Observation of Rothmannia capensis, Rietfontein, Gauteng. iNaturalist. Online. https://www.inaturalist.org/observations/123340263.
  • Douwes, E. 2021. Observation of Rothmannia fischeri subspecies moramballae, Ingwavuma, KwaZulu-Natal. iNaturalist. Online. https://www.inaturalist.org/observations/99063157.
  • Erasmus, R. 2023. Observation of Gardenia thunbergia, Westville, , KwaZulu-Natal. iNaturalist. Online. https://www.inaturalist.org/observations/192326925.
  • Glen, H.F. & Germishuizen, G. (compilers). 2010. Botanical exploration of southern Africa, edition 2. Strelitzia 26. South African National Biodiversity Institute, Pretoria.
  • Goldblatt, P. & Manning, J. 2000. Cape Plants. A conspectus of the Cape flora of South Africa. Strelitzia 9. National Botanical Institute, Pretoria & Missouri Botanical Garden, Missouri.
  • Gunn, M. & Codd, L.E. 1980. Botanical exploration of southern Africa. Balkema, Cape town.
  • Hankey, A. 2015. Observation of Rothmannia fischeri subspecies fischeri, Zimbali Estate, KwaZulu-Natal. iNaturalist. Online. https://www.inaturalist.org/observations/11114855.
  • Helme, N. 2024. Observation of Rothmannia capensis, Ga-Mogoadi, Limpopo. iNaturalist. Online. https://www.inaturalist.org/observations/201356266.
  • Hutchings, A., Scott, A.H., Lewis, G. & Cunningham, A.B. 1996. Zulu medicinal plants: an inventory. University of Natal Press, Pietermaritzburg.
  • Hyde, M.A., Wursten, B.T., Ballings, P. & Coates Palgrave, M. 2025. Rothmannia fischeri subsp. fischeri. Flora of Zimbabwe. Online. https://www.zimbabweflora.co.zw/speciesdata/species.php?species_id=155390.
  • Joffe, P. 2001. Creative gardening with indigenous plants. Briza Publications, Pretoria.
  • Johnstone, R. 2024. Observations of Rothmannia globosa, Amangwe Forest, KZN. iNaturalist. Online. https://www.inaturalist.org/observations/242492185; https://www.inaturalist.org/observations/242492160.
  • Louw, S. 2022. Observation of Rothmannia fischeri subspecies moramballae, Sodwana Bay National Park, KZN. iNaturalist. Online: https://www.inaturalist.org/observations/126519609.
  • Palmer, E. & Pitman, N. 1972. Trees of southern Africa. Balkema, Cape Town.
  • Plants of the World Online. 2024. Rothmannia Thunb. Online. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:327884-2.
  • South African National Biodiversity Institute (SANBI). 2024. The South African National Plant Checklist: 2024 official yearly release. Available online at http://hdl.handle.net/20.500.12143/6880.
  • Van Wyk, B. & Van Wyk, P. 1997. Field guide to trees of southern Africa. Struik, Cape Town.
  • Venter, F. & Venter, J. 1996. Making the most of indigenous trees. Briza Publications, Pretoria.
  • Watt, J.M. & Breyer-Brandwijk, M.G. 1962. The medicinal and poisonous plants of southern and eastern Africa , edn 2. Livingstone, Edinburgh & London.

Credits

Mulweli Maswoliedza
Foundational Biodiversity Science
Compton Herbarium
March 2025

Acknowledgements: the author thanks iNaturalist observers Nick Helme, Tjeerd de Wit, Rea Erasmus, Andrew Hankey, Errol Douwes, Sharon Louw and Richard Johnstone for sharing their photographs.

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