Catha forskalii A.Rich.
Catha inermis J.F.Gmel.
Celastrus edulis Vahl
Dillonia abyssinica Sacleux.
Methyscophyllum glaucum Eckl. & Zeyh.
Trigonotheca serrata Hochst.
Common Name: Khat
Khat is an erect, evergreen, glabrous tree growing up to 25 metres tall with dimorphic branching and a small pointed crown[
]. In cultivation it is a multi-stemmed shrub about 2.5 - 6 metres tall[
Khat has long been used as a masticatory and stimulant in Africa. It is both harvested from the wild and cultivated, with a history of cultivation going back to at least the 6th century AD[
]. The primary centre of origin is assumed to be in the south-western highlands of Ethiopia and its regular use as a stimulant is confined largely to Muslim communities of southern Arabia and eastern Africa. It was not known to the West until the end of the 18th century, and its use outside Africa is still largely confined to ethnic communities[
]. Khat use has grown tremendously in popularity, especially since the 1970’s, and the crop has become very profitable for farmers[
Eastern Africa - Cape Province to Ethiopia and into Arabia.
Evergreen submontane or medium altitude forest, usually near the margins, or in woodland often on rocky hills at elevations of 1,100 - 1,435 metres[
|Cultivation Status||Cultivated, Wild
Khat is cultivated in highland areas of the tropics and subtropics at elevations of 1,500 - 2,500 metres[
]. In these areas the average daily temperatures are around 16 - 22°c (within a total range of 6 - 32°c). The annual rainfall requirements are 800 - 1,000 mm over a period of 4 - 6 months[
]. Frost and high humidity are growth-limiting factors[
Khat can be grown in a wide range of moderately acid to alkaline soils, from sandy loams to heavy clays, sufficiently deep and well drained, with a high organic matter content in the topsoil[
]. It is not salt tolerant[
Khat is predominantly a smallholder crop; farmers intercrop young khat plants with food crops during the first 5 - 6 years, after which shade from the trees becomes too heavy for intercropping. A mixed cropping system of a few rows of khat alternated with one or two rows of coffee (Coffea arabica L.) is not uncommon in Ethiopia[
Khat is left to grow undisturbed for 3 - years, until about 0.8 - 1 metre tall. Most leaves are then removed to induce the development of young shoots for a first light harvest. Normal yield levels are reached at 5 - 8 years after planting. The height of plants is maintained at 2.5 - 5 metres by regular pruning. Trees can be rejuvenated by cutting back all stems close to ground level and allowing emerging suckers to develop into new stems[
]. In this way plantations can be kept productive for 50 - 75 years without replanting[
Flowering generally occurs during the rainy season, the fruits maturing within 4 months[
Khat is often grown for home or local consumption and only harvested when the need arises. Such khat plots are not very productive. In market-oriented khat producing regions of Yemen and Ethiopia, yields can be as high as 2 tonnes of fresh shoots per hectare per year for well-managed orchards. Average annual yields in Ethiopia are reported to be 800 - 1,000 kg/ha[
The genus Catha consists of one highly polymorphic species within which there are several cultivated forms[
]. In Ethiopia, farmers distinguish several cultivars, including 'Dallota' with small pale green leaves, 'Dimma' with medium-sized red leaves and 'Mohedella' with green to olive-green leaves. In Yemen, khat cultivars are sometimes named after a location, e.g. 'Sabri', 'Reimi', 'Taizi' and 'Mathani', or their coloration[
Khat is primarily used as a masticatory. Fresh young leaves, and sometimes the tender shoot tips, are chewed for their stimulating and mildly intoxicating effects.
Khat chewing is an age-old habit in rural areas to alleviate fatigue during fieldwork or to enliven religious and family gatherings. It is also used for its energizing effect by people such as car drivers to help them stay awake and alert on long journeys[
Larger leaves that are too hard for chewing and leaves that have lost their freshness may be dried and pulverized for the preparation of a paste with water, sugar or honey and sometimes also spices. The paste is chewed and swallowed in a similar manner to the fresh leaves[
Dried leaves are also used to prepare an infusion in the same way as tea, e.g. in South Africa, or they may be smoked liked tobacco, e.g. in Arabic countries[
In traditional African and Arabic medicine the leaves and roots of khat are considered a panacea against all sorts of ailments and diseases[
The wood of large trees is golden-yellow to brown, lustrous, straight grained, fine and even in texture, strong and moderately hard. It saws and planes well. When left to grow into large trees, it yields a fine timber for furniture and building, called Chirinda redwood in southern Africa[
]. The wood pulp makes excellent blotting paper[
Seed - best sown as soon as it is ripe since it quickly loses its viability[
]. Fresh seeds germinate within 15 - 20 days[
Nearly all propagation is by cuttings taken from orthotropic (alternate-leaved) shoots. Growth of rooted cuttings starts with the emergence of new orthotropic shoots with reddish bark and alternate leaves from buds above the leaf axils. These stems continue to increase in length for some two years before the first lateral branches with plagiotropic growth appear from the axils of the oldest leaves, bearing slightly smaller opposite leaves[
Suckers develop at the base of stems in response to heavy pruning[