Allamanda cathartica (golden trumpet vine)

Allamanda cathartica is a native of tropical South America, from Peru and Colombia eastwards to French Guiana and Brazil. It has also been recorded in Central America as far north as Honduras. It is widely cultivated elsewhere in the tropics.

This vigorous climbing plant has leathery evergreen leaves arranged in whorls of 4 at intervals along the stem and bright yellow flowers. The stems twine to 6 m or considerably more and contain milky sap.

The lance-shaped leaves are 6 cm long and 3 cm wide. Golden-yellow funnel-shaped flowers up to around 9 cm long and 6 cm in diameter are held in groups of 12 on short branches at the ends of shoots or in the leaf axils. The prickly seed pods contain winged seeds.

The form named ‘Hendersonii’ has larger flowers and is most commonly grown in Europe.

Hand-coloured engraving of Allamanda cathartica from Curtis's Botanical Magazine (1796) (Image: RBG Kew)

Three species of Allamanda have been illustrated in Curtis’s Botanical Magazine, under a variety of names. Allamanda cathartica appeared first in a hand-coloured engraving (artist unknown) in 1796 (see image, right). It was also illustrated in 1848 by W.H. Fitch as A. schottii, and as A. aubletii. In 1868 it was illustrated again by W. Fitch, under the name A. nobilis.

Curtis’s Botanical Magazine (Editor: Martyn Rix) provides an international forum of particular interest to botanists and horticulturists, plant ecologists and those with a special interest in botanical illustration.

Now well over two hundred years old, the Magazine is the longest running botanical periodical featuring colour illustrations of plants. Each four-part volume contains 24 plant portraits reproduced from watercolour originals by leading international botanical artists. Detailed but accessible articles combine horticultural and botanical information, history, conservation and economic uses of the plants described.

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The species is widespread both in the wild and cultivation but has not been evaluated according to IUCN Red List criteria.

Golden trumpet vine is widely cultivated as an ornamental. In some areas of the tropics it has escaped from cultivation and become a weed, most notably in the rain forests of northern Queensland.

Extracts of leaves, roots and flowers have been shown to have in vivo anti-tumour activity against leukaemia in mice, and against human carcinoma of the nasopharynx (nasal cavity and upper part of the throat) in culture. Leaf and root decoctions are used as a laxative and emetic in traditional medicine in a number of tropical countries, but large doses are toxic.

Golden trumpet vine needs plenty of direct sun to flower well and should be allowed to climb up a trellis or a similar support. Propagation is by stem-tip cuttings in spring.

Golden trumpet vine can be found in the Palm House and in the Waterlily House.

Pressed and dried, and alcohol-preserved specimens of Allamanda cathartica are held in Kew’s Herbarium, where they are available to researchers from around the world, by appointment. The details of some of these, including images, can be seen on-line in the Herbarium Catalogue.

Kew’s Economic Botany Collection includes samples of fruits, seeds and the wood of Allamanda cathartica.

A new species of Allamanda was described from north-eastern Brazil as recently as 2009 by Alessandro Rapini and Rita Fabiana de Souza-Silva. Rapini spent a year on a Kew fellowship working on the systematics and evolutionary relationships of New World Apocynaceae, in collaboration with Kew’s resident experts. He was subsequently able to demonstrate that the more evolutionarily derived groups of the family that diversified in Central and South America were the result of just four introductions from Africa over the last 20 million years.

Search Kew's databases for more information on this species

JSTOR Plant Science (includes images of Allamanda cathartica)

Curtis’s Botanical Magazine (Wiley-Blackwell)