Monday, March 10, 2014

Curtisia dentata (Assegai)

Curtisia dentata is a very handsome, medium to large evergreen tree with a dense, well rounded crown. In forest conditions or when grown as a single specimen in shadier areas, the Assegai grows tall and stately but when planted in full sun, these lovely trees develop a particularly dense and bushy crown. The creamy white to red, bitter fruits are attractive to fruit eating birds with the bush dove and the lourie being mainly responsible for the distribution of the seeds. Curtisia dentata is a protected tree in South Africa as the numbers throughout the country have been severely depleted due to over exploitation, as the bark is highly prized in traditional medicine.
Botanical Name
Curtisia dentata
Common Name
RSA National Tree No’
The magnificent Assegai is a truly excellent addition to the landscape. These superb trees can safely be planted in any built up or paved area as the roots are totally non-invasive. Another major advantage of planting these trees in an urban environment is that they create hardly any leaf litter while the tough branches ensure that they can withstand severe wind without any damage. These trees make superb specimen or shade trees while a tough, dense leafy screen or hedge can be created by planting a row along any sunny boundary or fence line. Where a landscape is being developed from scratch, Curtisia dentata will provide quick, long lasting and rewarding results.  
Height4 – 18 m
3 - 6 m
Growth Habit
Curtisia dentata is found growing naturally in coastal as well as montane forests throughout South Africa and Swaziland.
The bark on young trees is grey or reddish and smooth becoming dark as the tree matures with deep, somewhat squarish fissures.
The mostly ovate leaves are simple, opposite, thin, leathery and without stipules. Young leaves are bronze and velvety while mature leaves are smooth, dark green above and grey green covered with red brown hairs below. The margins are sharply and strongly toothed.
The small creamy flowers are inconspicuous and are borne in terminal sprays from October to March.
The round to oval fleshy fruits, are roughly pea sized and are usually white, cream or reddish in colour. They are crowned with the remains of a persistent calyx.
The fruits contain a small, four chambered nut each of which usually contain a small seed.
Growing regions
The Assagai tree is found in the Western Cape and up along the east coast to the Eastern Cape, Kwa Zulu Natal, Mpumalanga, Limpopo and inland towards Swaziland.
Growing conditions
Curtisia dentata grows well in full sun or light shade. Plant in a deep hole to which generous quantities of compost and organic fertilizer have been added. Cover soil around the tree with a deep layer of mulch. Water generously for the first three years.
Best season
 Spring - autumn
The Assegai will withstand moderate drought once established. Very young trees are sensitive to frost and may lose their leaves but more mature trees will tolerate some frost.
The seeds germinate readily. Remove the fleshy part of the fruit and sow the nut while still fresh. Keep warm and moist and the seeds should germinate within 3 – 4 weeks.
Growth rate
Fast, from 500mm to 1m per year.
The strong, durable timber of the Assegai tree is fine grained and has a reddish colour similar to mahogany. Over the years, this has led to the overexploitation of these magnificent trees as the wood was widely used for wagon making, floors, rafters and tool handles including assegais, as well as fine furniture and other household items. The bark is widely used for medicinal purposes such as the treatment of diarrhea, stomach ailments and as a blood purifier.
Curtisia dentata Flowers and FoliageCurtisia dentata BarkCurtisia dentata Fruit

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