Photo 2. Solitary, mature African tulip tree, Spathodea campanulata. Note the slightly buttressed trunk.
Photo 3. Clumps of flowers of African tulip tree, Spothodea campanulata, at the end of the branches.
Photo 4. Young African tulip trees, Spathodea campanulata, showing compound leaves (right) and flowers.
African tulip tree
Spathodea campanulata. It is a member of the Bignoniaceae.
Widespread. Asia, Africa, North, South and Central America, the Caribbean, Europe (Spain), Oceania. It is recorded from Australia, American Samoa, Cook Islands, Federated States of Micronesia. Fiji, French Polynesia, Guam, Kiribati, Marshall Islands, Nauru, New Caledonia, Niue, Northern Mariana Islands, Palau, Papua New Guinea, Samoa, Tonga, Vanuatu, and Wallis and Futuna. It is native to tropical west Africa.
An invasive tree that rapidly colonises disturbed areas - along roadsides, waterways, and at forest margins - in tropical and sub-tropical regions. It is especially common along creeks and gullies, or in thick stands in wetter parts of the Pacific islands (Photo 1). It can tolerate dry seasons for up to 6 months, and grows in soils that are poorly or well drained.
The trees grows to about 35 m, with spreading crown and slightly buttressed trunk (Photo 2). Leaves are compound, with 11-15 leaflets, up to 15 cm long, arranged in opposing pairs. Flowers occur in large dense clusters at the tips of branches (Photos 3&4). Individual flowers are enclosed in brownish boat-shaped sepals (about 5 cm long). The petals are reddish-orange, fused together and look somewhat like tulips (hence the name). Pollination is by birds, possibly bats. The seedpods are flattened, brown when mature and open releasing up to 500 light winged seeds (Photo 5).
The tree is particularly invasive in tropical islands of the Pacific and the Caribbean where it has been introduced because of its showy flowers. Rapid spread occurs due to production of masses of wind-dispersed seeds and profuse suckering. Spread is assisted by being planted as a garden ornamental and as a street tree.
The degree of 'weediness' of this tree has been argued in Pacific island countries over a number of years. Orapa1 summaries the arguments. There are some who consider the tree a positive addition to the flora. It quickly revegetates disturbed forests after fire in the absence of native species able to play that role. There is also a preference for the tree over fern on rugged hillsides.
The nectar of the flowers of the African tulip trees are toxic to native (stingless) bees, and kills them.
Some hold the view that the tree is viewed negatively only because it grows on land where crops have potential or native species might be growing.
However, negative impacts on biodiversity, as well as on agriculture and forestry, have been documented. For instance, in Fiji, Eastern Polynesia and some islands of the Bismarck Archipelago, Papua New Guinea, the tree grows aggressively, filling forest gaps through suckering and seed production allowing it to replace native hardwood species useful for building houses, canoes and other traditional wooden items. Further, African tulip trees are easily felled by storms, damaging homes, infrastructure, and people. The soft wood has little use, only for crates and shuttering.
A large tree with compound leaves arranged in pairs. Look for the characteristic 'tulip-like' red flowers at the tips of the branches, and the erect seed-pods splitting to release large numbers of wind-blown seeds.
Where this tree is invasive, consider regulations to prevent its distribution unless authorised.
The three most common species according to CABI are: Acherontia lachesis (greater death's head harkmoth), Hyblaea puera (teak defoliator, see Fact Sheet no. 435), and Psilogramma menephron (privet moth). Biological control using an isolate of the fungus, Ceratocystis, is reported from Cuba, killing trees in coffee plantations.
Pull out or dig out young seedlings. However, this is only effective if the trees are young when it is possible to remove the entire root system. Otherwise, suckers regrow from the roots.
In Australia, the herbicides triclopyr, picloram and glyphosate are registered for use against African tulip tree. Triclopyr + picloram is used as a stump treatment, and triclopyr + picloram or triclopyr + glyphosate as stem injections. Alternatively, the herbicides can be painted on the base of the trees to a height of 30 cm from the ground. In Palau, undiluted triclopyr or glyphosate is poured into notches cut 2.5 cm deep into the cambium around the stem.
AUTHOR Grahame Jackson
1Information from Warea Orapa (2017) Impact and management of invasive alien plants in Pacific island coummunities. In: Ellison CA, Sankaran KV, Murphy ST (eds) Invasive Alien Plants. CAB International. (https://www.cabi.org/ISC/FullTextPDF/2017/20173322107.pdf); and African tulip tree Spathodea companulata. Brisbane City Council weed identification tool. (https://weeds.brisbane.qld.gov.au/weeds/african-tulip-tree); and Weeds of Australia, Biosecurity Queensland Edition. Queensland Government. (https://keyserver.lucidcentral.org/weeds/data/media/Html/spathodea_campanulata.htm); and from Spathodea campanulata (African tulip tree) (2019). CABI Invasive Species Compendium. (https://www.cabi.org/isc/datasheet/51139). Photos 1,2&4 Forest and Kim Starr, Starr Environmental, Bugwood.org. Photo 3 Joy Viola, Northeastern University, Bugwood.org. Photo 5 Tony Pernas, USDI National Park Service, Bugwood.org.
Produced with support from the Australian Centre for International Agricultural Research under project HORT/2016/185: Responding to emerging pest and disease threats to horticulture in the Pacific islands, implemented by the University of Queensland and the Secretariat of the Pacific Community.
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