Anthocleista grandiflora

Forest Fever Tree
(Forest) Big Leaf
Big-leaf Fever Tree
Cabbage Tree
(Wild)Tobacco Tree
Grootblaarboom (A)
Boskoorsboom (A)
Wildetabakboom (A)
mophala (N.S)
luvungu (siSw)

Description

A most beautiful, statuesque and unmistakeable tree with a curious, unconventional appearance and an innate pathfinder in its forest home. It grows very large in the wild, yet still maintains an elegant appearance despite its enormous stature, with a tall, slender, unadorned bole of smooth grey bark and a compact crest of colossal, sleek leaves. The dwarfish branches, which are carried very high up on the tree, all arch gracefully upwards to create a rather sparse yet extensive crown. The butter coloured flowers are large, striking and richly scented but often escape notice as they are borne very high up and are often concealed by the lush foliage. It is the only member of the Gentianaceae family that reaches tree size in our country, has the largest leaves of any indigenous tree, and is officially a protected species.

SA Tree

Family

Loganiaceae (Strychnos & Buddleja family) – (APG: Gentianaceae)
A family of flowering plants classified in the order of Gentianales.
Consisting of about 13 genera, 4 of which occur in SA.
These plants are mainly tropical and subtropical, occurring worldwide.
Characteristically, plants from this family are usually in the form of woody vines, shrubs or trees with attractive, wonderfully fragranced flower clusters, leaflike appendages at the bases of leafstalks and fleshy or capsule-like fruits.

Habitat

These trees are most predominant in the mountainous eastern parts of the African continent and in South Africa they are usually encountered in the high rainfall, mid to low altitude north eastern parts of the escarpment.
They are a relatively common feature in moist, forested areas, as well as thick riverine vegetation and woodland areas, exposed swampy localities and mountainous regions from the coast to about 2000 m.
From Natal, parts of the Eastern Cape, Limpopo and Mpumalanga, extending into Swaziland and Zimbabwe.

Bark

The main stem is typically single and very straight, with a diameter of 500-1000 mm.
The branches are most often quite short and young branches have prominent leaf scars.
The bark is pale grey-brown in colour and rather smooth with faint horizontal ridges on older specimens.

Foliage

Deciduous.
The leaves are simple, very large, (200–700(–1200) mm × 80–350(–500) mm), narrowly obovate-oblong and are clustered at the ends of the branches.
They are carried in opposite; right angled and often unequal pairs along the stems and the leafstalks are either absent or heavily reduced (10-20 mm).
Above, the leaves are medium to dark green, paler green below, with prominent lateral veins and net-veining (8-17 pairs).
They are hairless, with a stiffly rubbery texture and entire, thickened and faintly, unevenly toothed margins.
The leaf tips are acutely or broadly rounded, and the bases are somewhat wedge-shaped to tapered.
Stipules are not present.

Flowers

The flowers are carried in rather large, erect, branched heads/panicles (120-450 mm long), at the tips of the branches.
The flowers are bisexual, somewhat trumpet-shaped and firmly fleshy or leathery, with a rich, jasmine-like, sweet scent.
The corolla tube is 25-40 mm long, and opens up at the throat to expose 11-16, slightly spreading or recurved, oblong to nearly lance-shaped lobes that are creamy-white within and greenish-white outside.
There are as many stamens as there are lobes, the former being equal and joined at the base, with rather short filaments.
September – January.

Fruit

An oval to broadly ellipsoid, fleshy drupe (30-40 x10-25 mm), with a slightly pointy or rounded tip.
The fruits are slightly rough but most often smooth textured and become slightly and irregularly wrinkled as they dry.
They ripen from green to a soft, yellow-brown.
They contain many, minute, obliquely ovoid-orbicular, dark brown seeds.
January – July.

Height

5-32 m

Spread

2-8 m

Medicinal

These trees have numerous medicinal uses across their distribution, with mainly the bark and leaves being used, less often the roots.
At least five triterpenoids were isolated from stem bark extracts, while the root bark yielded, amongst others, the secoiridoid sweroside.
The bark, taken as an enema, chewed or used in different infusions and mixtures, has been used extensively to treat diarrhoea, diabetes, epilepsy, fever, high blood pressure and venereal disease.
The bark and leaves are boiled in water and this infusion is said to help treat the symptoms of malaria.
In vitro tests have shown that leaf extracts have considerable anti-bacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis, but these extracts displayed no anti-malaria activity.
The leaves have strong laxative properties in high doses and have been made into general tonic.
In tropical Africa, crushed or burnet leaves are applied to teat wounds, and smoke from the burning leaves is said to deter malevolent spirits.
The roots are made into different concoctions which are used to treat asthma, kidney disease, diarrhoea and intestinal parasites.

Practical

The wood of these trees is light, whitish-yellow in colour, with no distinct demarcations, straight to spiral grained and medium to coarse textured and relatively heavy.
It is rather soft and brittle but works and saws well, does not split when nails are inserted into it, and takes a good finish.
It is often marked with somewhat horse-shoe shaped clusters of tiny air-holes.
It is predominantly used locally, as it does not have great value as a timber.
It is suitable for use in veneering, as well as light construction, flooring and joinery.
It makes good fruit boxes, crates, vats, carvings and smaller furniture.
Also makes a relatively good quality firewood.

Wildlife

The huge leaves are readily browsed by elephants and fallen leaves may occasionally be eaten by cattle.
The flowers attract bees, wasps, butterflies and a host of other insect lie, which then in turn lure many insectivorous bird species.
Fallen flowers are often eaten by smaller antelope.
The fruits are a firm favourite of fruit-eating birds, as well as monkeys, baboons, bushpigs, warthogs and fruit bats.

Advantages

This rather large, unusual and attractive tree makes a very interesting single specimen or focal plant in large, frost free gardens or parks.
It is grown for its ornamental and lovely shade giving properties.
It is a natural pioneer species that can grow in very wet sites where other vegetation may struggle.
It does not have an aggressive root system, so it can safely be planted in close proximity of paving and other permanent structures, but bear in mind the falling leaves can create quite a mess and it gets very tall.
The flowers and fruits attract a large variety of insect and animal life.

Tolerance

These are tropical trees which need protection from strong, cold winds, frost and drought.
They do not respond well to extreme cold, which may cause severe damage or even prove fatal in very young plants but can grow in colder areas if they are given adequate protection for at least their first 4-5 seasons.
They can withstand short dry spells but are not a generally drought hardy species.
It is not an appropriate choice for an exposed, dry, windy position or for small gardens.

Growth Rate

It has a moderate growth rate of about 120 cm per year with adequate water, shelter and food.
Under optimal conditions the growth rate may be slightly more, especially in young trees.
First flowering typically occurs after 4 or 5 years.

Lighting

Full sun or partial shade.
As the trees mature, more sun is needed for prolific flowering.

Soil & Water

These trees require a nutrient rich (humus), deep and well-drained loamy or peaty soil, with a neutral to very slightly acidic ph.
If planting into very sandy soils, add bone-meal, extra compost or liquid fertiliser and water often and deeply.
In clay soils, water slightly less frequently as they are quite moisture retentive.
Anthocleista grandiflora is a very water loving tree and languishes under dry conditions.
They require regular, deep drenching’s in medium to low rainfall zones, especially while still young, as well as on very hot days and during the warm summer months.

Propagation

Easily propagated from seed, cuttings or root suckers.
The seeds must be taken from fully ripened fruits.
Cut open the fruits and remove the pulp to expose the brown seeds.
After the seeds have been thoroughly washed and cleaned of any pulpy residue, they can be sown into seedling trays filled with a nutrient-rich, well drained mixture of fertiliser and fine river sand. (1:2).
The seeds should preferably be sown in spring or early summer.
Place the seedling trays in a warm, temperate and brightly lit area (not direct sunlight) and mist the soil often.
Germination is usually rapid, and once the plants have developed at least one set of true leaves they can be transplanted.
If growing from cuttings, take semi-or hardwood pieces, preferably actively growing shoots of the previous season and treat them with a rooting hormone.
Place these into coarse river sand or milled bark mixture, mist them often, making sure the soil stays wet but does not become waterlogged.