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Hagenia abyssinica (hagenia)

A beautiful tree from African mountain forests, hagenia is much-used in local medicine.

Illustration of Hagenia abyssinica (hagenia)

Illustration of Hagenia abyssinica (hagenia) (Image: Franz Eugen Köhler)

Species information

Scientific name: 

Hagenia abyssinica (Bruce) J.F.Gmel.

Common name: 

hagenia, kosso

Conservation status: 

Least Concern (LC) according to IUCN Red List criteria. Widespread and common.


Montane forests, forming dominant stands just above the moist forest/bamboo zone.

Key Uses: 

Medicine, timber.

Known hazards: 

Side-effects resulting from consumption of infusions of hagenia flowers have been reported.


Genus: Hagenia

About this species

An attractive African tree with soft leaves and hanging flower sprays, Hagenia abyssinica also has many uses. The wood is used for carving, carpentry, firewood and charcoal, and the flowers, roots and bark are used for medicinal purposes. An infusion of the flowers is used widely against tapeworms, and in Ethiopia this has been in use for so long that ‘the master has taken his kosso’ is a well-understood excuse meaning ‘he cannot see you’.


Discover more

Geography and distribution

Hagenia abyssinica is native to Eritrea, Ethiopia, Sudan, Uganda, Kenya, Congo-Kinshasa, Rwanda, Burundi, Tanzania, Zambia and Malawi.

Hagenia abyssinica (hagenia) woodland

Hagenia abyssinica (hagenia) woodland in Kinangop, Kenya.

It occurs in montane forests, especially in the upper forest region, at 2,300–3,300 m.

On most East African mountains, Hagenia abyssinica is common just below the tree-line (at about 3,000 metres above sea level), where it may form almost pure woodlands.


Overview: A tree up to 25 m tall, often with a crooked bole (unbranched part of the trunk). The bark is reddish brown, fissured and peeling. Trees are either male or female and only rarely are flowers of both sexes found on the same tree.

Leaves: Pinnate (divided like a feather) with 11–16 hairy, toothed leaflets (and sometimes additional, minute leaflets in-between). Each leaf is held on a winged leaf-stalk, measuring 30–40 cm long in total.

Flowers: Male flowers are orange to brown or white with 12–20 stamens (male, pollen-bearing parts); female flowers are red. The flowers do not have petals, and the colour is mostly due to the bracts (modified leaves). Flowers are borne in large, many-flowered, hanging groups, 30–60 cm long and up to 30 cm across.

Fruits: Small and dry, remaining hidden within the dried flower parts.

Threats and conservation

Hagenia abyssinica (hagenia) in Ethiopia

Hagenia abyssinica left standing after vegetation has been cleared (Ethiopia).

Hagenia is widespread and often common where it occurs, and plant parts are harvested sustainably for many of their uses (rather than, for example, by cutting down the whole tree).

Highly valued by locals for its uses, Hagenia abyssinica is often left standing when forest is cleared.

It has been suggested that hagenia needs fires to regenerate, and it is true that it often occurs in even-aged stands.


An infusion made using dried and pounded female flowers has been used widely against tapeworms. This treatment has been used for centuries in Ethiopia, but its use is now in decline due to availability of reliable alternatives. Health organisations discourage the use of this infusion as the dosage cannot be controlled, and serious side-effects of over-dosage have been reported.

Roots of Hagenia are cooked with meat to produce a soup that is consumed as a treatment for general illness and malaria. The bark has been used in treatments for diarrhoea and stomach ache.

The dark red wood is used for furniture, flooring and carving, but is not durable. An attractive tree, hagenia is sometimes planted as an ornamental.

This species at Kew

Specimens of Hagenia abyssinica flowers, stem, bark and wood are held in Kew’s Economic Botany Collection in the Sir Joseph Banks Building, where they are available to researchers by appointment.

References and credits

Assefa, B., Glatzel, G. & Buchmann, C. (2010). Ethnomedicinal uses of Hagenia abyssinica (Bruce) J.F.Gmel. among rural communities of Ethiopia. Journal of Ethnobiology and Ethnomedicine 6: 20.

Bekele-Tesemma, A., Birnie, A. & Tengnäs, B. (1993). Useful Trees and Shrubs for Ethiopia: Identification, Propagation and Management for Agricultural and Pastoral Communities. (Technical Handbook No. 5). Regional Soil Conservation Unit/SIDA, Nairobi, Kenya.

Graham, R. A. (1960). Rosaceae. In: Flora of Tropical East Africa, ed. O. B. E. Hubbard & E. Milne-Redhead. Crown Agents for Overseas Governments and Administrations, London, United Kingdom.

Jansen, P. C. M. (1981). Spices, Condiments and Medicinal Plants in Ethiopia, their Taxonomy and Agricultural Significance (Agricultural Research Reports 906). Centre for Agricultural Publishing and Documentation, Wageningen, Netherlands.

Kloos, H., Tekle, A., Yohannes, L., Yosef, A. & Lemma, A. (1978). Preliminary studies of traditional medicinal plants in nineteen markets in Ethiopia: use patterns and public health aspects. Ethiopian Medical Journal 16: 33–43.

Lange, S., Bussmann, R. W. & Beck, E. (1997). Stand structure and regeneration of the subalpine Hagenia abyssinica forests of Mt. Kenya. Botanica Acta 110: 473–480.

Woldemariam, T. Z., Linley, P. A. & Fell, A. F. (1990). Phytochemical studies on male and female flowers of Hagenia abyssinica by column chromatography, thin-layer chromatography and high-performance liquid chromatography. Analytical Proceedings 27: 178–179.

Kew Science Editor: Henk Beentje
Kew contributors: Iain Darbyshire
Copyediting: Emma Tredwell

While every effort has been taken to ensure that the information contained in these pages is reliable and complete, the notes on hazards, edibility and suchlike included here are recorded information and do not constitute recommendations. No responsibility will be taken for readers’ own actions.

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