Clerodendrum glabrum

(presently Rotheca glabrum)

Description

A neat, large shrub or small to medium, decorative tree with a curved or rounded crown of dark, lustrous green, sleek foliage, and attractively drooping branches. Wonderfully versatile and hardy, it has high potential as a garden ornamental, especially in tricky coastal gardens. The tree produces masses of dainty and elegant flowerheads that last for many months and are a magnet for butterflies.

SA Tree

Family

Lamiaceae (The Mint, Salvia and Deadnettle family)
A cosmopolitan family of flowering plants and the largest of the order Lamiales, with 236 genera and somewhat 7000 species.
Members can be found worldwide but occur mainly in the tropics or similar appropriate habitats.
The family includes mostly perennial or annual herbs, but some are woody shrubs and subshrubs, trees (teak) or infrequently, vines.
Many members are widely cultivated for their aromatic and often edible leaves, medicinal properties, ornamental qualities and ease of cultivation.
The leaves are generally simple, oppositely emerging or whorled, fragrant and contain volatile oils.
The flowers are usually arranged in clusters, are bilaterally symmetrical and bisexual.
The fruit is frequently a dry nutlet.
The family has conventionally been considered closely related to the Verbenaceae, but recent phylogenetic studies proposed that many genera classified in the Verbenaceae should be classified in the Lamiaceae.

Habitat

Found in the humid and warm, temperate regions of Africa, from Botswana to southern Africa, where it is widespread in the coastal dunes and coastal evergreen thickets, extending to the slopes of the Drakensberg in Natal.
Also, in Transkei and the Eastern Cape, Gauteng and Swaziland.
The trees can likewise be found in bushveld, along forest margins and in riverine scrub.

Bark

Pale grey to grey brown, becoming increasingly flaky and grooved as the tree matures.
The main stem is tall and bare or multi-stemmed, with a diameter of 400-500 mm.
The primary horizontal branches frequently have upright, slender or thick and hairy twigs, each with a layer of conspicuous white dots.

Foliage

Semi- deciduous.
The leaves can be very variable in shape and size, and have a strong, even unpleasant odour when crushed or bruised.
They are simple, oppositely arranged or in whorls of 3-6, without stipules.
Oval to elliptic obovate in shape, (25-100 x 10-65 mm), with a thinly fleshy, smooth texture.
Above, the leaves are glossy, glabrous and dark or grey-green, while the undersides are paler, and often covered in a layer of soft, velvety thin hairs with visibly sunken gland dots.
The margin is entire, slightly rolled under, and tends to fold up from the midrib, while the base is narrow and tapers to a pointed tip.
The leaves typically droop from an erect and scaly petiole (15-20 mm).

Flowers

Circular, compact inflorescence (30-140 mm diameter), consisting of small, tubular and five-petalled, white to pinkish-white flowers (8-10 mm).
Each flower has a conspicuously protruding, violet to mauve or white stamen, and gives off a lovely verbena-like or unpleasant scent.
The flowerheads are sometimes partly enclosed by the leaves and are produced in profusion.
(December – June, often year-round at the coast).

Fruit

Tightly packed bunches of globose, smooth, yellowish-white to cream berries, ripening to black and becoming increasingly wrinkled (6-10 mm diameter).
Each fruit is held in the withered, bowl-like remains of the calyx, and sometimes remain on the tree for many months.
Edible.
February – July

Height

Spread

Medicinal

Extracts from the leaves, bark and roots have been shown to containing numerous antihypertensive, anti-inflammatory, pain-relieving and tranquilising compounds.
The trees have a wide range of uses in traditional folk medicine.
Infusions of the leaves are used to treat colic, coughs, fever, colds, sore throats and chest ailments, and they are also crushed and applied topically to wounds and rashes.
Root concoctions are taken as emetics to treat rheumatism and are used against snakebites.
The bark, and occasionally also the leaves, is used as a dewormed and to protect against parasites.

Practical

A blue-grey dye can be extracted from the fruits, and the wood has traditionally been used as tinder to start fires.
The pale brown to whitish timber is suitable for carvings, tools, poles and small furniture items, and is often used by local people to construct their huts.
Poles are used as fish kraals.

Wildlife

The flowers attract mainly butterflies, but also bees, wasps, moths, ants and beetles.
The berries are eaten by numerous bird species, and game and livestock consume the leaves.
Certain insects feed off of the wood, and the Natal Bar butterfly breeds on this tree and also eats parts of the leaves.
Several caterpillar species are also known to frequently use the trees as food plants.

Advantages

A wonderfully versatile tree, with a non-aggressive root system.
For difficult coastal gardens, this is an ideal specimen, and as it can easily be trimmed to maintain a small shape, it will do well in large containers or small and informal gardens.
Also, a suitable bonsai subject. Its drooping crown and dense, low-branching growth habit makes it a good candidate for a windbreak, hedge or screen, filler or border plant. It provides light, dappled shade and is a good pioneer plant for new gardens.

Tolerance

The trees are remarkably tolerant of high temperatures, as well as the strong and salt-laden winds of the coast.
Periods of drought can be endured, but they are only half frost hardy.
Young and unestablished plants should be well sheltered for at least the first 3-4 years.

Growth Rate

Lighting

Soil & Water

The trees can tolerate poor and slightly saline soils, but prefer a loamy or peaty, humus rich soil with added compost.
They are water-wise (low water needs), but an extra layer of mulch can be strewn around the tree to help the soil retain moisture during very dry and hot periods.

Propagation

Propagate by seed, green hardwood cuttings or suckers.
Seeds should be sown in an organically rich mix of compost and river sand (1:2), the placed in a temperate, bright area and misted often.
Keep soil evenly moist but allow time to dry out between watering’s.
Cuttings and suckers (shoot growing from the base or root of a tree that gives rise to a new plant), can be placed in a similar mixture, and misted often.
A root stimulating hormone can be applied to cut-offs to accelerate growth.
Regardless of winter temperatures, prune the stems hard to the ground in early spring if compact plant form is desired.