Delonix regia (flamboyant)
Although widely cultivated in the tropics since the 19th century, the native habitat of flamboyant was unknown to science until the 1930s, when it was rediscovered growing in the wild in Madagascar.
About this species
Delonix regia is a very distinctive tree with large, bright red flowers. The genus name is derived from the Greek words delos (meaning conspicuous), and onyx, meaning claw, referring to the appearance of the spectacular flowers. The tree is commonly cultivated in the tropics and subtropics, including Madagascar, for its ornamental value, but is under increasing threat in its natural habitat due to habitat destruction.
Geography & Distribution
Restricted to the western dry forests of Madagascar, where it grows in the north and west of the Bemaraha massif, as well as in the dry forest around Antsiranana as far south as Daraina, and possibly also on Nosy Be. Delonix regia is however, also commonly cultivated throughout Madagascar and in many other tropical countries. It has become naturalised in some places, such as parts of southern Florida in the United States, and is invasive in parts of Australia, where it competes with native vegetation.
Delonix regia in Rustenburg, South Africa (Image: Wolfgang Stuppy)
Delonix regia is a tree and grows up to 30 m tall. Its trunk is tall and unbranched, sometimes with narrow, spreading buttresses extending from near the base. The bark is pale grey. The leaves are large with 10-25 pairs of pinnae, each with 30-60 opposite leaflets. The large, bright red flowers are about 10 cm in diameter, the upper petal with a large white to creamy-yellow blotch, flecked with red. The stamens (male parts) are dark red and the style (female part) is yellow. The pods are very long (40-70 cm), strap-shaped and flattened, containing up to 50 seeds each.
Little is known of the breeding system of D. regia. However, some self-incompatibility has been recorded. The species is thought to be pollinated by sunbirds.
A specimen cultivated in Martinique, with golden-yellow, unspotted flowers, was described by Henri Stehlé (1909-1983) as Delonix regia var. flavida. This variant is unknown in the wild and should be recognised only as a cultivar - D. regia 'Flavida'.
Threats & Conservation
Although flamboyant is reasonably widespread in Madagascar, the habitat in which it grows is severely fragmented and seriously threatened by slash-and-burn agriculture, charcoal production, grazing by domestic cattle and goats, and uncontrolled bush fires.
Kew’s Millennium Seed Bank Partnership has collected seeds of Delonix regia and is storing them ex situ in the Kew seed bank in the UK, as well as in Madagascar.
Delonix regia is widely planted in the tropics and subtropics as an ornamental tree in streets and parks. It is fast-growing and develops an umbrella-shaped crown, making it a valuable shade tree. The wood is of little value, although it is durable and resistant to water, and has been used for making fence posts. The seeds of D. regia are sometimes used as beads, and there has been some research on the use of the gum obtained from the dried seeds as a binder in the manufacture of tablets, such as paracetamol.
Delonix regia is often depicted on postage stamps of countries around the world which have tropical or subtropical climates, from the small island of Anguilla (one of the British Overseas Territories in the Caribbean) to one of the largest countries, China.
Millennium Seed Bank: Seed storage
Kew's Millennium Seed Bank Partnership aims to save plant life world wide, focusing on plants under threat and those of most use in the future. Seeds are dried, packaged and stored at a sub-zero temperature in our seed bank vault.
Description of seeds: Average 1,000 seed weight = 408g.
Number of seed collections stored in the Millennium Seed Bank: Three.
Seed storage behaviour: Orthodox (the seeds of this plant survive drying without significant reduction in their viability, and are therefore amenable to long-term frozen storage such as at the MSB)
Germination testing: 100 % germination was achieved with pre-sowing treatments (seed scarified - chipped with a scalpel) on a germination medium of 1% agar, at a cycle of 8 hours of daylight at 25°C, and 16 hours of darkness at 10°C.
Composition values: Oil content = 4.77%. Protein content = 17.1%.
Delonix regia from Madagascar, cultivated (Image: Gwilym Lewis)
Delonix regia requires well-drained soils in full sun, and is well-suited to maritime conditions in the tropics and subtropics. However, its roots are wide-spreading and can damage paving, land drains, and the foundations of nearby buildings. The tree has brittle branches which are shed readily. Underplanting with other species is difficult because of the spreading root system. Care needs to be taken in choosing the right site for planting, well away from hard landscape features so as to avoid damage.
Delonix regia is suitable for glasshouse or conservatory cultivation in temperate regions. It has been grown at Kew in the past, and was planted in free-draining compost and kept in a warm zone with a minimum temperature of 13°C and bright light. It requires plenty of water when in full growth, but watering should be reduced in the winter.
This species at Kew
A bracelet featuring the brown seeds of D. regia (Image: RBG Kew)
Dried and spirit-preserved specimens of Delonix regia are held in the behind-the-scenes Herbarium at Kew, where they are made available to researchers from around the world, by appointment. The details of some of these specimens can be seen on-line in the Herbarium Catalogue.
Delonix regia from Madagascar (Image: Gwilym Lewis)
The CEPF Madagascar Vegetation Mapping Project - vegetation map of Madagascar
SEPASAL (Survey of Economic Plants for Arid and Semi-Arid Lands)
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