Tetradenia riparia

Musk Bush
Misty Plume Bush
Ginger Bush
Gemmerbos (A)
Watersalie (A)
Iboza
Ibozane (Z)

Description

A large, robust, densely bushy and softly woody perennial shrub, rarely a tree, with slightly succulent stems and rounded, thick, velvety and brilliantly green leaves that emit a strong aromatic fragrance reminiscent of lavender or fresh ginger, even when dry. During the otherwise bland winter months, these plants burst forth with clusters of mist-like, white to lilac flowers, that, although small, are produced in such masses that they seem to outweigh the rest of the plant.
Even the smallest of plants will bear flowers. This species was first described in 1830 and has a wealth of medicinal uses. The specific name is derived from the Latin word riparius and refers to its favoured natural habitat of river and stream banks.

SA Tree

668.2

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

In its native habitat, the Ginger Bush is generally found in damp, warm areas, especially along river and stream banks, as well as the margins of forests and woodlands.
These shrubs can also be found in drier areas, such as valleys and rocky outcrops or hillsides.
They frequent the wetter eastern and southern parts of the country, from the coast to elevations of about 1700 m above sea-level.
Limpopo, Mpumalanga, Natal, Transkei, extending to Swaziland, Zimbabwe, Namibia, and Angola, then northwards into tropical east Africa.

Bark

The stems are smooth textured, with the exception of the younger stems, which have a thin, furry layer of glandular hairs and a reddish tinge.
The Ginger Bush has an irregular branch pattern, and the stems are quite stout, but brittle at the bases.
Older stems are a pale grey-brown and have a somewhat succulent texture.

Foliage

Semi-deciduous, depending on the climate.
The leaves are ovate-oblong to almost round or heart-shaped (30-180 x 30-140 mm), with irregularly, somewhat bluntly toothed margins.
They are a bright green colour and are slightly sticky to the touch due to the presence of whitish, velvety, glandular hairs on both surfaces.
Venation is indented above, prominent below, and they exude a strong, aromatic scent when handled.
The leaves may turn yellow and fall in autumn, usually just before flowering commences.

Flowers

Large, spreading inflorescence spikes, clustered together to form many-branched panicles, carried in the axils of leaves or the ends of branches.
Each flower spike consists of many small, pale mauve, white or sometimes pink tamarisk-like flowers, and flowers are often produced while the plant is still leafless.
Male and female flowers are carried on separate plants and differ with regards to shape and size.
The male spikes are slightly longer (20-80 mm), and have a somewhat “misty” appearance, while the female spikes are more compact (10-30 mm).
Flowering is typically most prolific during the winter months, but will continue, albeit at a lesser pace, throughout the year. (May-August)

Height

1.5-3 m

Spread

2-3 m

Medicinal

The plant contains a number of medicinally active compounds, and leaves and young stems are commonly used in traditional medicine.
An essential oil can be extracted from the plant, and has shown both insecticidal and insect repellent properties, as well as antimalarial (against two strains of Plasmodium falciparum) and antinociceptive actions.
Leaf extracts also displayed antimicrobial and antiviral activity against the growth of Staphylococcus aureus, Candida albicans, Mycobacterium smegmatis, Microsporum canis, Trichophyton mentagrophytes and Bacillus subtilis.
An infusion of the leaves and roots is used as an emetic, and simply inhaling the aroma of the crushed leaves is said to bring relief from headaches.
In folk medicine, it is used to treat dental abscesses and toothaches, malaria, diseases induced by worms, bacteria, or fungi, and is also valued as an antiseptic.
Leaf infusions are used to treat a variety of respiratory ailments including coughs and bronchitis, as well as colic, colds, fever, dropsy, diarrhoea, stomach aches, a sore throat, gingivitis or mouth ulcers.

Practical

The cut flower stems last for a long time, especially if steeped in water, and make excellent additions to floral arrangements.
In certain places in Africa, the leaves are added to stored seeds and grains to keep out weevils and other harmful pests.

Warnings

This shrub needs to be managed and cut back often, as it has a tendency to grow and spread very rapidly and can take over entire patches of garden if left to its own devices

Wildlife

The flowers attract a variety of insect life; butterflies, honey- and Carpenter bees, wasps, beetles and more.
It is believed to be a host plant to the nocturnal Trichoplusia molybdian moth species.
The vast array of insect life enticed by the bountiful floral display will help bring many insectivorous bird species to the garden.

Advantages

It is grown and valued for its ornamental and medicinal qualities.
It produces its most dazzling floral display in winter, making it the ideal choice for adding colour and life to any landscape when there is little else to be appreciated.
It makes for a pleasing addition to background foliage, with large, bright green leaves in summer and spring, while in autumn the yellowing leaves add another splash of colour.
It can tolerate difficult coastal conditions, and also looks beautiful in a wild or rock garden setting.
It responds well to pruning (it is recommended that it be trimmed down heavily once a year, after flowering to encourage future flowering and keep a neat shape) and can easily be pruned into a variety of desired shapes.
It makes an excellent container plant and will look marvellous on a large patio.
Does not grow very big, so it suited for smaller gardens or areas of limited space.
It is fast growing, flowers within its first year, or while still very small, and will colonise open spaces rapidly.
It is too flimsy to form a complete, sturdy screen, and is therefore not an ideal specimen for screen or hedge planting, it will however work very well if planted beside a water feature or on the edge of a forest clump.

Tolerance

These shrubs are only moderately to marginally frost hardy, able to tolerate only very slight frost.
In cold climates, they are best suited to pot culture or sheltered, warm spots such as against a north–facing wall or on a succulent rockery.
They prefer moderate to high rainfall areas and languish in prolonged dry conditions.
Not drought resistant.
They also need protection from strong winds.

Growth Rate

Fast to very fast growing- 600-1000 mm per year can be expected

Lighting

Full sun, but in very hot climates a bit of midday shade or light shade is essential.

Soil & Water

They prefer a light, well-drained, loamy soil, with a neutral ph.
Peaty, humus rich soils, with added sand for drainage, are also a good choice, but these shrubs will also accept less favourable soil conditions, such as sandy and slightly clay.
Mulch well.
It prefers more water in summer, and less in winter, making it an ideal water-wise plant for summer rainfall areas.
Moderate to high water needs, it does not like excessively dry conditions.

Propagation

Easily propagated from cuttings or truncheons taken in spring.
Propagation by means of seed is possible, but the seeds may be difficult to obtain if your garden has only male or female plants in it.
Seeds can be harvested after flowering, when the seedpods have fully ripened- they should be black.
Cut the flower stalk before the seed is naturally dispersed.
The seeds can be stored in a cool, dark, well-ventilated room.
Prior to sowing, the seeds can be treated with a pre-emergence fungicide to prevent damping off.
Sow in a well-drained mixture of equal parts fine river sand and fertiliser.
Place the trays in a bright, temperate area, and mist daily.