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Proteas |
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Some of the most spectacular species in the diverse vegetation of the Cape region of South Africa are the proteas. When they were first seen in Europe in the early years of the seventeenth century, they were mistaken for thistles because of their large cup-shaped inflorescences made up of numerous small flowers. The genus shows an amazing diversity of shape and form, ranging from trees to low-growing shrubs. In recognition of this diversity, it was named after the Greek sea god, Proteus, who was able to change his appearance. There are over 114 species of protea in Africa, 82 of which occur in southern Africa. Of these 69 are found in the coastal region of Cape Province. The genus is in the family Proteaceae, which is confined to the southern hemisphere. Other plants in the same family are found in Australia (eg Banksia, Telopea and Hakea) and South America (eg Chilean fire bush - Embothrium coccineum). |
All proteas have simple rather leathery leaves, in many different shapes and sizes. The massed flowers in the inflorescence are surrounded by petal-like bracts and are often mistaken for single flowers. All erect proteas are pollinated by sugarbirds, which visit the flowers for their nectar. Sugarbirds use dry protea flowers to make their nests. Some low-growing species which bear their flowers close to the ground are pollinated by mice.
The king protea (P. cynaroides), now the national flower of South Africa, is the most spectacular species with inflorescences up to 30 cm across. Pink (or occasionally crimson) pointed outer bracts covered with silky hairs surround the central mound of lilac flowers. This species was introduced to Britain from South Africa in 1775 by Francis Masson, Kew's first official plant collector, and was first induced to flower here in 1803. Another specimen bloomed in 1826, but after that the species did not flower again in this country until 1986, when the plant in Kew's Temperate House produced five blooms. This specimen now flowers prolifically every year.
The sugarbush or honey flower (P. repens) has flower heads up to 15 cm wide, ranging from pink-red to white in colour. The flowers produce large quantities of nectar, so much so that the bud actually glistens. A sweet syrup (bossiesroop) made from the flowers was used by early colonists in South Africa as a sweetening agent and to treat coughs and chest complaints.
Two groups of proteas can be distinguished by the shape of their bracts. P. neriifolia is an example of a bearded protea. It has cup-shaped flower heads 13 cm long, with pink, red or white bracts with black bearded tips. Another group has spoon-shaped bracts; this includes P. susannae with its reddish-brown bracts and P. obtusifolia with its smooth bracts which vary in colour from bright-red to white.
In the wild, many proteas grow in mountainous regions, on acid soils that are free-draining and low in nutrients. They experience winter rainfall, dry windy summers and periods of drought. The plants have developed a number of different adaptations to cope with these adverse conditions. Many have small leathery leaves, sometimes covered with hairs, to restrict water-loss. The dwarf species, with their stems below ground, are particularly drought resistant. Specialised roots increase the uptake of nutrients from the infertile soils. Swellings at the base of the stems, called lignotubers, can withstand the fires that often devastate the areas where proteas grow. New shoots develop from the lignotubers and enable the plant to recolonise burnt areas.
In cultivation, the plants require acid soils (pH below 6.5) which are low in nitrates and phosphates. The soil should be a well-drained compost of low pH. A mixture of 2 parts sand to 1 part loam and 1 part leaf-mould, with the addition of a small amount of organic fertiliser, such as bonemeal, is suitable.
Before they are sown, the seeds should be soaked in water for 24 hours. They should then be scattered over the surface of the compost and covered with dry sand. The compost must not be allowed to dry out or germination may be stopped. Germination may take up to 3 months, and the seedlings should be potted individually as soon as they are large enough to handle. They should not be moved again because the delicate specialised roots will be damaged. The plants should be hardened off gradually from their germination temperature of 15-18°C. They should only be watered when the soil dries out and care should be taken to avoid damping off. Since they cannot tolerate high phosphate levels, the plants should only be fed with phosphate-free fertilisers.
Proteas will not grow where the temperature drops below 0-2°C, but they can be grown successfully out of doors in sheltered areas and against south-facing walls in southern Britain, for example at Tresco in the Isles of Scilly. They grow better if given protection in glasshouses or conservatories. Glasshouse-grown proteas require very good ventilation because the plants do not tolerate high humidity. In the eighteenth century, the use of steam heating in glasshouses, with resultant high humidity, was the immediate cause of the reduction in successful protea cultivation in Britain.
Several different species of protea, including those species described above, are grown in the south octagon of the Temperate House. Pictures of proteas in flower can be seen in the Marianne North Gallery. Marianne North was a Victorian painter who travelled around the world painting flowers in their natural habitats. When she was brought a specimen of P. cynaroides to paint, she said that she 'almost cried with joy' when she saw the inflorescences with 'bracts like pink satin, tinted at the base with green, and a perfect pyramid of yellow flowers rose in the centre'.
Beckett, K., 1987. The RHS Encyclopaedia of House Plants. Guild
Publishing
Eliovson, S., 1973. Proteas for Pleasure. Macmillan
Lighton, C., 1973. Cape Floral Kingdom. 2nd ed. Juta and Company
Perry, F., 1987. Flowers of the World. Spring Books
Rourke, J. P., 1980. The Proteas of Southern Africa. Purnell
Rousseau, F., 1970. The Proteaceae of South Africa. Purnell
Vogts, M., 1982. South Africa's Proteaceae: Know them and Grow them.
C. Struik
The National Botanical Gardens of South Africa have produced a leaflet on growing Cape Proteaceae.