Euphorbia pulcherrima (poinsettia)
A small tree or shrub from Mexico and Guatemala, poinsettia is cultivated for its striking red bracts, and potted forms are the basis of a lucrative Christmas industry.
About this species
Euphorbia pulcherrima is a popular garden plant in tropical and subtropical areas and is well-known as a pot-plant associated with winter festivities in temperate regions. The common English name ‘poinsettia’ was chosen by historian and gardener William H. Prescott in the mid 19th century to honour Joel Roberts Poinsett who introduced the species to the USA in 1828.
The genus Euphorbia was named in honour of Euphorbus, the Greek physician to King Juba II of Mauretania (a learned scholar of natural history) in the 1st century AD, who used the latex of Euphorbia species for medicinal purposes.
Although many other species of Euphorbia are poisonous, poinsettia contains only low levels of chemical irritants.
Geography & Distribution
Euphorbia pulcherrima is native to southern Mexico and Guatemala.
It is also widely cultivated throughout the tropics and subtropics, and escaped plants have become invasive weeds in parts of Africa, India and the Canary Islands.
Each cyathium bears a yellow, two-lipped gland (Image: Wolfgang Stuppy)
Overview: Small tree or shrub up to 4 m tall with few, stout, hairless branches.
Leaves: Relatively thin, usually 12–20 cm long with pointed tips. Borne on long, slender petioles (leaf stalks).
Flowers: Each tiny, petal-less female flower is surrounded by male flowers in a cup-shaped series of bracts known as a cyathium. Each cyathium bears a two-lipped, yellow gland. The green and yellow cyathia are in turn surrounded by a series of large, bright red bracts.
Fruits: Tri-lobed capsules, about 1.5 × 1.5–2.0 cm.
Seeds: Ovoid, more or less smooth, pale grey.
Poinsettia is widely cultivated as a garden ornamental in tropical and subtropical areas and grown commercially as a pot-plant, in particular for sale during the winter period. One of the top-selling potted flowering plants in the USA, poinsettias are the basis of a multi-million dollar Christmas industry. Poinsettias have long been associated with the Christian celebration of Christmas and have been used to decorate altars in Guatemala.
A range of cultivars are available, for example:
Euphorbia pulcherrima ‘Barbara Ecke Supreme’ – bright blood-red bracts
E. pulcherrima ‘Ecke’s White’ – cream-coloured bracts
E. pulcherrima ‘Rosea’ – pale pink, darkly veined bracts
To produce compact, well-branched plants in commerce, rooted cuttings are treated with growth retardants. They are exposed to long periods of darkness to produce brightly coloured bracts (caused by production of anthocyanins).
Poinsettia latex has been used as a hair removal cream in Mexico and Guatemala. A red dye has been obtained from the bracts. In Guatemala, the latex has been used as a remedy for toothache and to cause vomiting. Poultices of leaves have been applied to treat aches and pains.
The red colouration of the bracts appears after exposure to long winter nights (Image: Wolfgang Stuppy)
With a little care, it is possible to keep potted poinsettias for re-use the following winter. Once the festive season is over, watering should be reduced.
After the plant has dropped its leaves, the stems should be cut back by half to two thirds and the plant placed in a shaded position at 10–15°C. Watering should be kept to a minimum.
In early summer poinsettia should be re-potted and placed in bright, indirect light, where the temperature is about 18°C. The red coloration of the bracts should appear after the plant is kept in total darkness for more than 12 hours per night.
This species at Kew
Marianne North's painting of poinsettia: Flor de Pascua or Easter Flower at Morro Velho Brazil
Pressed and dried specimens of Euphorbia pulcherrima are held in Kew’s Herbarium, where they are available to researchers from around the world, by appointment. The details of some of these can be seen online in Kew’s Herbarium Catalogue.
A specimen of poinsettia wood is held in Kew’s Economic Botany Collection.
Kew’s Illustration Collection includes the following paintings by artist Marianne North, which feature poinsettias: Flor de Pascua or Easter Flower at Morro Velho Brazil and The Taj Mahal at Agra North-West India.
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