This season's tree: Delonix regia
By Jean-Jacques Segalen (jjacques) December 16, 2013
Summer on Reunion is globally red; not only because of the crimson dress of Santa Claus (who usually comes here surfing, no snow for his sleigh...) but the bright red impression comes from fruits and flowers. The fruits are those of the litchi tree (Litchi sinensis) which has been introduced in a previous article but the flowers, ah, the flowers! Imagine a tree with massive trunk, heavy main branches forming a well-shaped solid frame onto which long curved branches form an elegant large cupola totally covered by a mass of scarlet flowers. Yes, a stunning vision, even more effective since those flowers appear on bare trees as this species is deciduous, shedding its foliage during the dry season.
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| No more doubt,|| summer || is here!|
Delonix regia, (syn. Poinciana regia) is known as "royal poinciana," "peacock flower," "flame of the forest," "flame tree" in English, "Gulmohar" in India, "flamboyant" in French, "arbol de fuego" in Spanish, "alamboronala, sarongadra, tsiombivositra, hitssankisa, hitsakitsana and kitskitsabe" in the various Malagasy languages. As you might guess, this tree originates in Madagascar where it was discovered in the year 1824 in the area of Antsiranana, Mahajanga and Majunga in the northeastern part of the "Red Island." Regrettably enough it is close to extinction in its natural setting because of massive deforestation, trees felling for charcoal and general destruction of nature.
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| Various shades of red....|| to orange || and back to red|
This very handsome tree belongs to the Fabaceae family (bean family) and Caesalpinioideae subfamily, and the genus Delonix includes ten different species mostly from Madagascar and two from Africa and Asia, but the only one grown worldwide is the flame of the forest; it is nowadays found in every tropical place and will be thriving in humid climates with dry winters. It will not do fine in areas with permanent humidity like Hong Kong and will in no way take freezing temperatures (minimum 15°C or 59°F). The Latin name of the genus ‘Delonix' is related to the shape of the petals; ‘delos' means ‘obvious' and ‘onyx' means ‘claw' while the species name ‘regia' means ‘royal' as allusion to the imposing bearing of the tree.
| Delicate foliage|| sometimes compared|| to ferns...|
Just like many plants of the Fabaceae family the leaves are composite and even bipennate (the leaves are divided in leaflets which are themselves divided again) pale green to emerald green. In Burkina Faso (Western Africa) they are boiled and used to cure colds. The species is deciduous and may grow to 15m (50 feet) high with a very spreading top; the bark is grey and smooth and yields pigments and resin. The roots system is rather superficial and extends to a distance, it will therefore inhibit the growth of other species in its immediate vicinity and if plants are wanted underneath only shallow rooted ones will do fine. The tree's roots would easily dislodge paving stones and concrete slabs.
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| Close-up of the flowers|| Flowers and flower buds|| Standard and stamens|
Flowers are usually red but will vary from orange or pale red to a bright scarlet, the petals are clawed as explained above and the standard (also called ‘banner' or central petal) is white with red spotting as can be seen in the close-up shots, stamens are orange. Note that there exists a yellow flame of the forest, quite rare in cultivation (I know of only one tree on Reunion Island while there are hundreds if not thousands of red ones...) which is sterile and has to be propagated by means of grafting unto a red stock. The fruits are woody pods which can be as long as 60cm (2 feet), brown when ripe and contain elongated hard seeds about the size of a date stone. Those pods are solidly attached to the tree and some even stay until the following bloom; they can be used as fuel. As the seeds are relatively free in the pods those can be used as musical instruments for rhythm like in some African countries.
|Yes, a flame...||...can also...|| ...be yellow!|
The seeds are also widely used for decoration purposes, mostly for necklaces and bracelets or to adorn musical instruments, water pots and so on, they are also edible once boiled. But beware; raw seeds contain glycopeptides (phytohemaglutinin) which causes vomiting, diarrhea, sleeping and tachycardia, so you are warned! If you harvest them to propagate the tree you have to keep in mind the fact that this species comes from a savanna area and has thus developed a specific adaptation to periodic bush-fires. After a fire has burnt down trees and bushes a great many sprouting can be seen where Delonix regia used to grow while very little seeds growing would be monitored during rainy years and very scarce fires. This means that the seeds require a heat treatment in order to raise the natural dormancy, a clever mechanism also found in giant redwoods (Sequoia sempervirens), baobab trees (Adansonia sp.), the endemic tamarind of Reunion (Acacia heterophylla) and a great number of plants in Australia and South Africa. So as you do not want to burn down your kitchen or attic just to get trees growing the easy and simple way of doing is by pouring simmering water onto the seeds and letting them soak for 24 hours before sowing; this will greatly increase your chance of having a good percentage of germination. Growing can be rather rapid and flowering will happen after some four to five years and the tree starts getting its distinctive shape after only ten years (a remarkably short time for a tree although it may seem long for a man...)
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| Massive grey trunk|| smooth bark|| and lichen for decoration...|
The wood is used for fuel, charcoal, building and carpentry. Of course its main use is ornamental, it resists amazingly well to drought once established, will take salty air with a smile and is also resistant to pollution so it will happily grow even if the air is full of car exhaust gases and other modern problems. Its only drawback is that the wood is quite fragile so branches may break during storms or violent winds and if grown too close to roads and pavements the roots will interfere some day. It requires well-drained soils; permanent soaked grounds would rapidly kill it. If pruning must be undertaken, the soonest the better as drastic pruning will not be tolerated, large limbs will not heal correctly thus leaving entry ways to diseases such as wood fungi and insects.
| A pods harvest|| Open pod shows seed|| Ready to sow!|
I hope all the readers will have at least once the chance to admire a flame of the forest in full bloom, it is just like a live firework without the noise...simply make sure to travel in tropical locations at the end of dry season and you will be rewarded!
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