The tree's vivid red/vermilion/orange/yellow flowers and bright green foliage make it an exceptionally striking sight.
The Royal Poinciana is endemic to Madagascar, where it is found in the West Malagasy forest. In the wild it is endangered, but it is widely cultivated elsewhere. In addition to its ornamental value, it is also a useful shade tree in tropical conditions, because it usually grows to a modest height (typically around 5 m, though it can reach as high as 12 m) but spreads widely, and its dense foliage provides full shade. In areas with a marked dry season, it sheds its leaves during the drought, but in other areas it is virtually evergreen.
The flowers are large, with four spreading scarlet or orange-red petals up to 8 cm long, and a fifth upright petal called the standard, which is slightly larger and spotted with yellow and white. The naturally occurring variety flavida has yellow flowers. Seed pods are dark brown and can be up to 60 cm long and 5 cm wide; the individual seeds, however, are small, weighing around 0.4 g on average. The compound leaves have a feathery appearance and are a characteristic light, bright green. They are doubly pinnate: Each leaf is 30-50 cm long and has 20 to 40 pairs of primary leaflets or pinnae on it, and each of these is further divided into 10-20 pairs of secondary leaflets or pinnules.
The Royal Poinciana requires a tropical or near-tropical climate, but can tolerate drought and salty conditions. It is very widely grown in the Caribbean, Hong Kong, the Canary Islands, Taiwan and southern China, and is also the city tree of Tainan, Taiwan and Xiamen, Fujian Province, People's Republic of China. National Cheng Kung University, a university located in Tainan, put Royal Poinciana on its emblem.
In the United States and United States Commonwealth, it grows only in South Florida, Southwest Florida, the Rio Grande Valley of South Texas, ranging from the low deserts of Southern Arizona (to as high as Tucson), Southern California, Hawaii, Puerto Rico, U.S. Virgin Islands, Guam and the Commonwealth of the Northern Mariana Islands, where it is the official tree of the islands. It is much adored in the Caribbean; for example, many Puerto Rican paintings feature Flamboyant Trees. The Poinciana is also the national flower of St. Kitts and Nevis. Also Phillipe de Longviliers de Poincy was the first Lieutenant Governor of St. Kitts.
The Royal Poinciana is regarded as naturalised in many of the locations where it is grown, and is seen by some as an invasive species in some parts of Australia, partly because its dense shade and root system prevent the growth of other species under it. It is also found in India, where it is referred to as the Gulmohar. In West Bengal (India) and Bangladesh it is called Krishnachura.
The seed pods of the Royal Poincianas are used in the Caribbean as a percussion instrument known as the shak-shak or maraca.