Albizia saman - Rain tree, black wood of Haiti, genisara tree

Albizia saman, nicknamed the Rain Tree or Black Wood of Haiti, boasts a majestic habit and a broad parasol-shaped crown. Its delicate foliage closes up in the rain, and its airy pink and white flowers offer a refined spectacle. This beautiful tropical tree struggles with temperatures below 10°C: it will need to be grown in a pot in most of our climates and brought indoors during winter. You can place it in a bright conservatory or heated greenhouse. It may be attempted in open ground in southern Europe, or even in very sheltered gardens on the French Riviera or Corsica.

Albizia saman, formerly named Samanea saman, belongs to the Fabaceae family and the Mimosoideae subfamily. Native to neotropical regions, its natural range extends from Mexico to Brazil, including countries like Guatemala, Peru, and Bolivia. It has been widely introduced to other tropical regions, particularly Southeast Asia and some Pacific islands, where it is often planted as a shade tree.

Albizia saman is a tree with bipinnate foliage, reaching a height of 15 to 25 m in the wild, with a dense, spreading crown that can extend up to 30 m in diameter. Of course, it will not reach these dimensions in our latitudes, let alone in a pot. Its often short and twisted trunk has grey-brown bark, smooth in young specimens, becoming fissured with age. The branches are velvety to the touch. The 15 to 40 cm long leaves are composed of 4 to 6 pairs of opposite pinnae, each bearing 4 to 8 pairs of leaflets. The oblong and asymmetrical leaflets measure about 4 to 5 cm long and 1.8 to 3.2 cm wide, with a smooth upper surface and a finely hairy underside. A notable characteristic is the nyctinastic movement of the leaves, which close at night or during rainy weather, allowing rain to pass through—hence the common name Rain Tree. The foliage is evergreen in humid tropical forests but becomes deciduous in the dry season in tropical dry forests. When grown in a greenhouse under optimal temperature and humidity conditions, Albizia saman generally retains its foliage year-round.

Flowering occurs at the start of the rainy season in the wild. In the Northern Hemisphere, particularly in Europe and the United States, the flowering period of Albizia saman varies depending on local climate conditions and cultivation practices. When grown in pots and maintained in controlled environments, such as greenhouses or conservatories, the tree may flower from late spring to early autumn, typically from May to September. However, this period can fluctuate depending on care, light exposure, and ambient temperatures. This flowering is characterised by subglobose heads of 5 to 7 cm in diameter, composed of white flowers at the base and pink at the top, with prominent stamens. The central flowers of the heads are distinct from the others, often nectar-rich. The fruits are straight, black pods when ripe, measuring between 12 and 20 cm in length and about 1.2 cm thick. They are indehiscent and contain numerous oblong seeds, embedded in a brownish, sweet pulp, appreciated by livestock and some local populations.

Albizia saman is known for its rapid growth, especially under favourable climatic conditions, with annual rainfall between 600 and 3,000 mm and average temperatures of 20 to 35°C. It tolerates a wide range of soils, including neutral to moderately acidic ones, with a pH between 5.5 and 8.5. Locally, the tree is frequently used as a source of timber, fodder, and shade in agricultural plantations.

Albizia saman, with its majestic habit and broad parasol-shaped crown, is ideal for creating a tropical atmosphere in a spacious greenhouse or conservatory. To accompany this tree, consider, for example, a Red Banana (Musa acuminata 'Red Dacca'), a Bird of Paradise (Strelitzia reginae), and a Bougainvillea glabra 'Variegata' to add height. Together, these plants will create a lush and dynamic scene.

Albizia saman is famous for a remarkable specimen located in the Parc de l'Habitation Céron in Martinique. This majestic tree, over 300 years old, is considered one of the largest in the Lesser Antilles. It has survived numerous cyclones as well as the devastating eruption of Mount Pelée in 1902. In 2017, it was named "Tree of the Year" in France, a testament to its resilience and historical significance.