Common Name: Kousso

General Information

Hagenia abyssinica is a rather slender open-crowned dioecious tree growing from 5 - 25 metres tall[]. The unbuttressed bole is usually short and crooked with the bark peeling in strips and sometimes very thick on old stems[, ].
The tree is a highly valued medicinal plant, being commonly harvested from the wild for local use. It used to be traded internationally as an anthelmintic, but with the advent of chemical alternatives its use has greatly reduced. It is still sold in local markets in Ethiopia[]. The plant is sometimes deliberately left in farmland or derived grassland and may be occasionally planted where it occurs naturally because of its medicinal properties[]. The tree also provides a timber that makes a good fuel and charcoal, and is used in soil stabilization projects. An attractive tree with its strands of red flowers, it is suitable for planting in amenity areas[].

Known Hazards

None known

Botanical References

Range

Eastern Africa - Central African Republic to Ethiopia, south to Tanzania and Zambia.

Habitat

Often dominant in the woodland zone just above the mountain bamboo at elevations of 2,000 - 3,000 metres[]. It occurs in undifferentiated afro-montane forest and dry single dominant afro-montane forest; at lower altitudes often at forest margins[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Tree
Height	15.00 m
Pollinators	Bees
Self-fertile	No
Cultivation Status	Cultivated, Ornamental, Semi-cultivated, Wild

Cultivation Details

A plant of the dry to moist tropics, where it is found at elevations from 1,800 - 4,300 metres. It grows best in areas where annual daytime temperatures are within the range 25 - 32°c, but can tolerate 5 - 36°c[]. It prefers a mean annual rainfall in the range 1,000 - 1,600mm, but tolerates 400 - 1,800mm[].
Prefers a sunny position[]. Prefers a fertile, well-drained, medium-textured soil[]. Prefers a pH in the range 6 - 7.5, tolerating 5.5 - 8.5[].
Flowering and seeding can be observed almost throughout the year, with a break in the months with the coldest temperatures[].
Mature trees are tolerant of fire, and heavy fires create ideal germination conditions for the small wind-dispersed seeds[].
The plant is unable to regenerate in areas suffering from a high level of grazing. Young trees have poor competitive ability[].
Plants can recover well after a forest fire[].
The plant is usually dioecious, but with some polygamous specimens[].

Edible Uses

The seeds are used as a condiment or spice[].

Medicinal

The flowers of Kousso are very commonly used as an anthelmintic in traditional medicine in Africa. Generally, though, this is a very strong medicine with toxic properties and it must not be taken in large quantities - strong doses can cause fainting, visual disorders or even death[]. The plant is also sometimes taken as an abortifacient[].

The dried and pounded female inflorescence is used as an anthelmintic (especially for expelling tapeworm)[]. Traditionally, a tea made from the flowers would be drunk every three months to rid the body of tapeworms[]. The tea is drunk before breakfast; about 30 - 180 minutes later its laxative action starts. The head of the tapeworm (scolex) is seldom expelled, so the worm can regrow, hence the need to repeat the treatment every 1 - 3 months[].

The roots are cooked with meat and the soup drunk for treating general illness and malaria[].

The bark may be pounded, added to cold water and the liquid drunk as a remedy for diarrhoea and stomach-ache[].

The active principles in the flowers are phloroglucinol derivatives, called kosins: kosotoxin, protokosin, kosidin, α-kosin and β-kosin.[].
The efficacy of kosso as anthelmintic depends on dosage and the health of the patient. Strong doses of kosso can cause fainting, visual disorders or even death. Usually a dose of 8 - 16g of dried flowers is taken, but some people use as much as 35g.
Although it is often stated that female flowers should be used, most tests reveal no difference in effect between male and female flowers. They can be as effective as the chemical anthelmintics dichlorophen, niclosamide and praziquantel[].
Side effects may include irritation of the gastrointestinal tract, salivation, nausea, headache, fainting spells, general weakness and diarrhoea. Some believe that side-effects are more severe when male flowers are used, and that male flowers have greater emetic activity[].
In-vitro tests have shown cytotoxic effects against carcinomous cells[].

Agroforestry Uses:

The trees are employed in soil-conservation activities[].
A fire-resistant species, it can be planted to form a firebreak[].
The tree constantly sheds leaves, providing mulch and green manure[].
In an experiment in Makete District Tanzania, grain yield of wheat was measured on eight different farms for a two-year period. The threshed wheat yield under a pruned H. abyssinica canopy averaged 810 kg/ha compared to 600kg/ha on parts of the field located at least 30 metres from a tree[].

Other Uses

The bark is used for dyeing textiles yellowish red[].

The heartwood is dark red to red-brown; the sapwood is creamy yellow. The grain is straight, with occasionally some silver grain when cut radially. The wood is medium soft, moderately heavy but not durable, and is subject to attack by borers and termites[, ]. It is fairly easy to saw; planing may be difficult due to interlocked grain, but the moulding, boring and turning are satisfactory; pre-boring before screwing is essential; nail-holding power is high. The wood has a handsome appearance and is used for making furniture, poles, flooring, carving and cabinet making[, ].
A good source of firewood and charcoal[].

Propagation

Seed - they can be stored dry without special requirements for 6 - 12 months. Germination is about 40 - 60% after 2 - 3 weeks from sowing. The seed is very light: there are 400 - 500 seeds per gram[].

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