Poinciana

Delonix regia

Family:     Fabaceae   Origin: Poincianas are native to Madagascar

The common name Poinciana comes from the tree originally being placed in the genus of the same name. It has also been called flamboyant and, along with many other trees, flame tree.

It has become naturalised in many countries into which it has been introduced, especially in Asian countries near the equator: in China, for example. For this reason it should be treated with some caution by responsible gardeners in Brisbane.

Arboriculture

Growth form

Royal Poinciana, in good climates, grows up to 9 to 12 metres high. They have a wide umbrella canopy that usually grows wider than the tree is tall. This has made poinciana useful in hot climates as a shade tree because of its height and thick, wide canopy of leaves.

Trunk

The poinciana has a relatively smooth trunk of a light brown color. It can start branching too low to the ground for people to walk under it, so should be pruned while still juvenile to eliminate low scaffold branches.

Flowering

For several weeks in spring and summer Poinciana is covered with exuberant clusters of flame-red flowers, 10 to 12 cm across. Even up close the individual flowers are striking. They have four fan-shaped scarlet or orange-red petals about 7.5 cm long, and one upright slightly larger petal–the standard–which is marked with yellow and white.

The flowering ability of a tree is determined by age, genetics and environment. Poincianas shouldn’t be expected to bloom until reaching at least six years of age, sometimes older. If they have been grown from a parent or parents with good flowering genes they should flower prolifically with, ironically, either good nutrition or under stress.

Poinciana flower

Close up of a poinciana flower

Foliage

The poinciana’s compound leaves are striking. They are lacy and fernlike, bipinnate, and 30.5 to 50.8 cm long with 20 to 40 pairs of primary leaflets, each divided into a number of pairs of secondary leaflets.
poinciana foliage

Fruits

Being in the Fabaceae family, Poincianas are legumes so their fruit really is a bean. Their seeds start out green and soft, but become brown and woody as they age. They look like flat pods up to 60cm long and 5cm wide).
poinciana seed pods

Management

Propagation

Poinciana are commonly propagated by soaking the seeds for up to 24 hours in water before planting them in warm, moist soil. Instead of soaking, the seeds can also be nicked open allowing water to get inside the pods, and then planted immediately.

An alternative method is to take a branch and cut it into 30 centimeter long sections, and then plant those in soil. Rooting hormone (auxin) will aid the cutting to take hold.

Cultivation

The Poinciana requires a tropical or near-tropical climate and full sunlight, but can tolerate drought and salty conditions. Poinciana prefers an open, free-draining sandy or loamy soil enriched with organic matter. The tree does not like heavy or clay soils and flowers more profusely when kept slightly dry. It is also tolerant of somewhat acidic and alkaline soils.

Phosphatic fertilizer can aid in flowering and can be applied at the start of Spring. Juveniles can also be fertilized in Summer and Autumn with a 15:5:15 or similiar fertilizer. Growing Poincianas is an exercise in balance. We also apply organic fertilizer subterraneously when pruning poincianas to aid their recovery.

Poincianas grow relatively fast, around 1.5 metres a year.

Issues

Borers

Poncianas are susceptible to borers that usually attack Australian natives. They should be examined externally for tell-tale borer holes. Peel aside a little bark from any damaged wood and look for pin-holes.

Borers can be killed mechanically by poking wire down the hole if caught early. Usually, it’s better to have us treat the tree by injecting an insecticide which is absorbed by the tree and kills the borers as they eat the wood.

If in doubt, have us examine the tree as we can use instruments to check for internal borer activity. If left untreated, Poincianas may collapse due to damage to the heartwood and the resulting rot.

poiciana borer

Brown Root Rot

Poincianas can also be attacked by the same Fusariam fungus that causes brown root rot, killing many jacarandas in Brisbane’s parks a few years ago. The Brisbane City Council has established a management plan using a Trichoderma species of fungi, though it is still in a trial phase. The DPI are extending the trial to other regions and will publish results in 2016. Officially, removal of affected trees on private property is currently recommended.

Poincianas should not have mulch with pieces of wood greater than 25mm length applied to the soil within its canopy as this can aid in transmission of the Fusarium fungus.

Further reading and sources

Schwarze, Francis WMR, et al. “Evaluation of an antagonistic Trichoderma strain for reducing the rate of wood decomposition by the white rot fungus Phellinus noxius.” Biological Control 61.2 (2012): 160-168.

David’s field notes

Perhaps the biggest issue I see from day to day with Poincianas is poor pruning technique. Poinciana branches that have been cut out from the trunk will do one of two things. Firstly, they can simply die, becoming dead wood that later falls from the tree. Until they fall they expose the tree to the entry of bacteria, fungi, insect and borer attack.

Secondly, and even more commonly, watersprouts will grow from the cut branch. Poincianas have strong epicormic growth; that is, they have dormant buds along the branches. As a result new, spindly branches grow much faster than the section that was removed so the property owner has to have the tree pruned regularly. This is another example of it being more economical to have something done right, the first time.

Further, poor pruning practices destroys the structural integrity of the tree as solid watersprouts are prone to snapping. I recommend only having Poincianas pruned by an arborist.
Bad pruning of a poinciana has left this tree dangerous and damaged

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Comments

  1. Sorin says

    Hi David,

    I live in the Southern Brisbane suburbs. In the past week I noticed that my potted 4 year old poincianas seem to be drying out and I am thinking it is a bit a early in the winter to loose their leaves. I am concerned that they might be dying and looking for advice to save them. I can send pictures if you are interested to have a look.

    Thank you,
    Sorin

  2. Lia says

    I live a few km from beach in Perth and would love to plant a poinciana in my front yard but it is South facing in front of a triple story house and there is little sun there and quite windy
    Would it be too cold to grow one there?
    Any suggestions for an other shade loving soft beautiful tree would be very welcome
    Lia

  3. John says

    Hi ,
    Thanks good read. .

    JUST wondering about proximity to the house . We planted our seedling in 2010 , now getting big (and beautiful!) .
    It’s 6 or 7 feet from the house front?
    Thanks in advance

  4. Peta says

    Hello,
    I live on a cattle property outside Taroom, Qld
    We have several poincianas outside our garden fence. We spreAd some old chook manure ( had a semi load from a chook farm) around some trees… Within a month those trees had grown rich deep green leaves, and many more leaves… We then finished the man urging job, and all look healthy
    Inside the garden a very big (10y/o) poincianna died… Very quickly ! It had had the same manure treatment
    When my husband cut it for removal, we found many borer holes
    Another garden poincianna now has big lumps of beer bottle coloured sap on its branches….. This tree did develop dead brNches in it, we have cut them out- back to the main trunk
    There are also splits ( 1-3″ long) in the trunk and branches
    Is there a systemic treatment we can use for borers?
    Sorry to be longwinded, not sure what to do to safe guard our trees
    In appreciation
    Peta Adams

  5. Lee says

    We have a poinciana approx 6 yrs old. It seems this year to have lots of seed pods on it. Should i remove them or leave them to fall naturally?

  6. VElvet Friar says

    I planted a Poinciana about 12-18 months ago and have had continued growth upwards and upwards of new leaves, no flowers as yet. There is only one stork or trunk if I cut it, will it continue to grow? I live north of Townsville, beachfront position. MY question is, should I cut off the top of the trunk for it spread and form a canopy? I need some advice as local nurseries seem not to know what I should do. Many thanks in anticipation for your reply.

  7. Simon says

    Hi David,

    Our neighbours have a poinciana that overhangs our driveway. At this time of year (Oct/Nov) it drops black “spots” all over our cars and stains the paintwork – especially on white cars.

    Are these spots bug poo, or something to do with the flowers?

    Is there any way to stop them other than not parking under it?

    Thanks

    Simon

  8. Pam Ross says

    l have a Poinciana tree that is 50 years old. It has been heavily pruned but has come back beautifully. We have pavers under the tree around a small garden which is up against the trunk. The pavers are lifting due to the large roots ;pushing them up. Is it okay to take up the pavers and prune the roots? Will this kill the tree? We don’t want it to die as it has great sentimental value. We live in Mackay, Qld.+ Thanking you in anticipation.

    Pam

    • Matthew Bower says

      Hi my name is Matt.
      I live on the gold coast and have a beautiful old Poinciana in the front yard and also need to cut a large section of the roots out on one side of the tree to fit a new carport.
      I am very worried about cutting the roots as I don’t want to loose our beautiful tree.
      if you get an answer about your root problems could you be so kind as to email me some advice.
      Thankyou
      Kind regards Matt

  9. margaret carman says

    Hi
    I have a poinciana planted 3 years ago, now approx 4 mts in height.
    Is it possible to transplant it. Am moving to a new property and the tree has great sentimental value.
    Have been told to dig a large circular pit around it, approx half mt from the trunk, line the hole with black plastic, water the tree very well and allow the roots to regrow into the plastic lined bowl.
    Are there likely to be any vertical deep roots? So far the largest we have come across would be about the size of 50c piece, at about half a meter depth. The tree is just making its move to shoot as we have had a very late spring; temperatures here in Perth are just beginning to warm up….
    Many thanks
    Marg

  10. Erin says

    Hi David

    I have returned to a property after 5 years which has a very large poinciana. When I left it was very healthy with lots of green foliage and flowered beautifully.

    It is now quite bare and showing no signs of flowering this year plus on one or two of the larger branches there appears to be bark breaking away.

    I had an issue at the property in the last few months with a concealed water leak that water logged my hedge and close to killed it but the hedge next to the tree is fine.

    I live in Brisbane

    Any ideas?

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