Voacanga thouarsii

Description

These trees belong to an Old-World genus comprising of 12 species found mainly in Africa and Asia. Voacanga thouarsii grows as a small to medium sized tree with a straight, often low-branching and orthotropic trunk. It tends to grow in a distinctly dichotomous habit, with new growth arising from a single point and expanding upwards. New growth appears at the apices, and the solitary, terete stem expands accordingly. The Wild Frangipani has a rounded, somewhat spreading but well-shaped crown of large, sleek leaves and impressive, creamy-white flowers with a cloying scent. The flowers are succeeded by paired, subglobose, pale and dark green-spotted fruits that split to reveal a vivid, deep orange pulp embedded with seeds. Subsequent to flowering, the topmost axillary buds develop into branches, so that the growth is sympodial. A highly valued medicinal tree.

SA Tree

Family

Apocynaceae (Dogbane family)
A family of trees, shrubs, woody vines and herbs belonging to the order of Gentianales, with more than 400 genera and 4500 species, found primarily in the tropical and subtropical areas of the world.
Many members possess a milky or watery latex, which is often poisonous, but is also used medicinally or as bird lime.
Leaves are typically simple and opposite, or arranged in whorls of 3 or more, with smooth, entire margins.
Flowers are small and grouped in clusters, rarely solitary, and the fruits are either berries or drupes, usually occurring in pairs but sometimes singly.
Many members are highly decorative, such as the Frangipani and Impala Lily (Adenium multiflorum).

Habitat

Found almost throughout tropical Africa, extending downwards toward Swaziland, Zambia, Zimbabwe and also Madagascar.
They occur along the eastern coastline of South Africa, from sea-level to altitudes of about 1500 m.
Voacanga frequents wet, swampy areas and is a common resident in damp places along the fringes of evergreen, riverine or swamp forests of Natal and Pondoland.
It can also sometimes be found in open, marshy grassland situations.

Bark

The bole is typically straight, with a diameter of 400 – 800mm, repeatedly dichotomously branched with branches being produced from fairly low down on the stem.
The bark is smooth on young trees and gradually becomes rougher.
Young branches are light green with a scattering of pale raised white dots, which may diminish with age; and the bark is a pale greyish-brown and irregularly mottled.
A white latex or milky sap is present.

Foliage

Evergreen
The leaves are simple, opposite and clustered towards the tips of branchlets.
They are narrowly obovate to oblong-oblanceolate (80-160 x 25-55 mm), with a broadly tapering to nearly rounded or rarely notched apex and a narrowly wedge-shaped base that runs down to the leafstalk.
They have a rather thick rubbery or leathery texture, are glossy and dark green above, dull green below with a scattering of pale patches and domatia in the axils of the veins.
The midrib is prominent below, and there are 8-12 pairs of extensive but relatively indistinct secondary veins.
The margin is entire, and the petiole (10-25 mm long) is somewhat concealed by the decurrent leaf base.
The stipules are rather small and sheath-like but fall early and leave a conspicuous rim between the leaves.

Flowers

Rather large, showy, waxy and somewhat fleshy, white, greenish-white to creamy yellow flowers with a diameter of up to 45 mm.
The corolla tube (10-14 mm long), is narrowly to broadly obcordate and the widely tubular or cylindrical calyx tends to partly enclose it.
The flowers are most often produced in pairs or few-flowered heads and are held towards the ends of the branchlets on sturdy stalks.
They have a strong, saccharine scent.
August – March.

Fruit

Paired, obliquely subspherical mericarps (60-90 mm diameter), that are joined at the base.
The fruits have a thickly leathery texture and are dark green with whitish-yellow or paler green mottling.
Often, only one of the fruits develop at a time, and they tend to split open while still on the tree to reveal numerous smallish seeds that are implanted in a vivid, deep orange, fleshy and somewhat sticky pulp.
February – August.

Height

Spread

Medicinal

These trees contain numerous medically active compounds, of which indole alkaloids are the most important and abundant.
Various pars of the tree, especially the seeds, are in high demand by various European pharmaceutical companies.
A compound is extracted from the seeds which is used as an additive in medicines that depress the central nervous system and is used in the treatment of cerebral vascular disorders.
In traditional folk medicine, nearly all the parts of this tree have been utilised to treat a variety of illness’ and disorders.
The bark, roots and seeds are used in various preparations to treat abdominal pains, high blood pressure, heart diseases and cancer.
Concoctions and infusion of the stem bark, leaves, roots and the latex are used to bring relief from rheumatic afflictions and treat fungal infections, scabies and eczema.
These concoctions are also applied to wounds, boils and open sores and the latex is said to lessen toothache.

Practical

The latex is often used as a birdlime and has also been used as a glue for various small items and to repair baskets.
The wood is burnt to produce a vegetable salt.
The inner bark yields a moderately durable fibre which is used to make nets in certain African countries.
The wood is reddish brown, fairly tough but difficult to work and holds very little value.
It is used as a firewood and to make charcoal, as well as fence posts, smaller ornaments, handles and tools.
Occasionally used in the construction of traditional huts.

Warnings

Wildlife

The flowers lure insects, bees and butterflies, which may lure insectivorous birds.
The fruits are eaten by monkeys, baboons, birds and occasionally people.

Advantages

A tall, beautiful, well-shaped tree with showy, strongly scented flowers and interesting, attractive fruits.
It can be planted in wet areas where other plants may struggle.
When planted in groves, they add a wonderful tropical atmosphere to the garden.
It responds very well to coppicing and pollarding.
Voacanga thouarsii is a natural pioneer species and can help with the rehabilitation of disturbed areas.
It is often planted along various watercourses to assist with water and soil preservation.
Provides food for many small garden and wild critters.

Tolerance

A plant of wet, warm climates that languished in dry condition and is frost sensitive.
Established trees may be able to tolerate light frost but they should be very well protected for at least their first 5 season.
Withstands waterlogged soils and seasonal flooding.

Growth Rate

Moderate to fast, depending on locality, quality of soil and amount of water received.

Lighting

Soil & Water

These trees prefer a moist, deep and nutrient rich soil, but tolerate sandy and somewhat clay growing mediums too.
It can colonize disturbed habitats easily and is seen as a pioneer species.
It requires swampy, moist conditions to grow at its best, and therefore has high water requirements.

Propagation

Mostly grown from seeds sown in spring or early summer.
The seeds should be harvested from the fruits very soon after they split open and can then be directly sown or removed from their sticky arils which inhibit germination.
Seeds can be soaked in warm or cold water for 12 hours to help remove this substance and improve germination rate.
Sow the seeds into a well-drained and loose medium of fine river sand and compost (2:1) and place in a warm, bright area.
Mist the soil often making sure it stays moist but not overly wet.
The seeds can be treated with a pre- or post-emergence fungicide to prevent mildew setting in.