The carob tree (Ceratonia siliqua)

This article was published in the "Hortuskrant" of September 2005 of the "Botanical Garden of Amsterdam"

by Fred Triep  

On this webpage I give attention to the carob tree, in connexion with the theme “Fruits and Seeds” of the Hortus Magazine. This tree makes large pods of thirty to forty cm length.
The carob tree (Ceratonia siliqua) is native to the eastern part of the Mediterranean, but was spread in historical times in the whole area. The tree was later brought to the New World, where it thrives in Mediterranean areas with hot, dry summers and cool winters (California, Australia).

naar de Nederlandstalige pagina
(to the original Dutch version)

The tree

The tree can become 7 till 10 meters high. He is slowly grown: the first flowers appear only after 5 till 6 years. The pinnately compound leaves are scattered along the stems. They are made up of six to ten small leaflets of two and a half to six cm in length, each of which is oval in shape with a rounded point.

Click on the thumbnails when you want to see the large pictures

Left: The carob tree in the Botanical Garden of Amsterdam  with a bench under it (in the subtropical part of the `Three Climates Greenhouse`)
A branch of the carob tree in the Botanical Garden of Amsterdam with leaves
Totally right: A branch of a carob tree on the coast of south Italy

Photo's : Fred Triep

Foto 3 van de Johannesbroodboom


The flowers appear in small plumes from September and are arranged in a spiral to the flowering axis. In most plants the flowers are budding at the new plant parts, but in this tree they arise on the old bare wood, a phenomenon called cauliflory. The small flowers are inconspicuous and six to twenty-two mm long. Although this tree belongs to the family Fabaceae, the flower of the carob does not look like that of other members of this family. Plants of the Fabaceae have asymmetric flowers that consist of five petals. The two lower petals form the keel, which encloses the pistil and stamens. On either side of this are two petals, which are called the swords. The upward petal is called the flag. The flower as a whole resembles a butterfly. But in the carob tree the petals are absent. There are sepals, which are green to red.

Foto 4 van de Johannesbroodboom Click on the thumbnails when you want to see the large pictures

Left above: Branch with leaves and halfway the branch inflorescences
Left under:
Different inflorescences, each consisting of more than one flower, developed on the bare branch
Right above: Detail of young flowers, the stamens are still visible
Right under: Detail of old flowers, the stamen are disappeared and the fruits (pods) are developing

Photo's : Fred Triep

Foto 6 van de Johannesbroodboom
Foto 5 van de Johannesbroodboom Foto 7 van de Johannesbroodboom

Pollination and fruiting

The trees have unisexual flowers (only male flowers or only female flowers) or hermaphroditic flowers. The different sexes grow on different trees. Insects (bees and flies) ensure the pollination, but researchers have discovered that even the wind can do that. The pods and beans of the carob tree are very nutritious. The name Johannisbroodboom in Dutch and German comes from the tradition that John the Baptist would have eaten the pods. The tree is also called carob tree, which derived via the Spanish (algaroba) from the Arabic kharoub. The pods contain five to fifteen seeds. The ancient Greeks discovered that the beans have often identical weight. Therefore, the beans were used in the comparison of weights. Thus arose the name carat, a weight that  is roughly equivalent to 200 milligrams. Later this term was used in gold and gems.

Carobeboom met vruchten 1 Click on the thumbnails when you want to see the large pictures

Left: A carob tree in south Spain with fruits (pods)
The fruits (pods) of a carob tree

Photo's : Fred Triep

Vruchten van de carobe boom

Use of the pods

The pods are in Southern Europe often used as fodder. In tough times, they were also eaten by people. The pods contain a lot of sugar and eating it has a laxative effect. Often the pods are ground into a powder, which is rich in fiber and sweet.
The beans themselves are rich in protein. They are ground into flour, which can be baked. Also, this flour is used as a substitute for chocolate, by mixing it with cold or hot milk.
In the food industry carob flour is used as an emulsifier in various food products (ice cream, sauces, salads, etc.). In Europe it is permitted as a food additive under number E 410.

Where can you find them?

The carob trees tolerate only light frosts: up to four degrees. Therefore they occur in Spain and Portugal only along the coast. Nevertheless, Spain is the largest producer of the pods, but they are now also grown commercially in Australia.
Only recently (in 1980) there was described a second species from the genus Ceratonia, namely C. oreothauma. Of this species there are two subspecies, one from Oman and one from Somalia.
In the Botanical Garden of Amsterdam you can find the carob tree in the subtropical part of the “Drie- Klimaten Kas” (Three Climates Greenhouse), immediately to the right of the entrance. Under the tree is a bench, so you can look the tree comfortable


Oleg Polunin and Anthony Huxley
Flowers of the Mediterranean
Chatto and Windus,
London, 1974, vijfde druk

L. Battle and J. Tous
Promotions and use of underutilized and neglected crops, 
17 Carob tree- Ceratonia siliqua
International Plant Genetic Resources Institute, 1997

Stevens, P.F. (2001 onwards).
Angiosperm Phylogeny Website. Version 5, May 2004

Neerlands tuin- Johannesbroodboom, Ceratonia,



This page is newly created on Monday 7 January 2013.

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