The African tulip tree (Spathodea campanulata) is an evergreen tree native to West Africa. It has been introduced throughout the tropics, and, has naturalised in many parts of the Pacific. It favours moist habitats and will grow best in sheltered tropical areas. It is invasive in Hawaii, Fiji, Guam, Vanuatu, the Cook Islands and Samoa, and is a potential invader in several other tropical locations.
The African tulip tree is described as follows a “large tree with a stout, tapering often somewhat buttressed trunk, branches thickish, marked with small white lenticels, subglabrous to thinly puberulent, reaches heights of 25 m; leaves usually opposite (rarely 3 at a node), very widely diverging, up to 50cm long, (7-) 11-15 (-17) leaflets broadly elliptic or ovate, entire, to 15 x 7.5cm, with 7-8 principal veins on each side, puberulent and prominent beneath, apex very slightly acuminate, base somewhat asymmetrically obtuse, lower leaflets tending to be reflexed, petiolule short, 2-3mm, rachis nearly straight, brownish-puberulent, petiole up to 6cm long, thickened at base; raceme 8-10cm long on a peduncle of about the same length, with a pair of reduced leaves about halfway up, rachis and pedicels thick, brownish puberulent, bracts subtending pedicels lanceolate, curved, about 1cm long, caducous, pair of bractlets near summit of pedicel similar, opposite; calyx strongly curved upward, asymmetric, about 5cm long, tapering, somewhat ribbed, splitting at anthesis to within a fewmm of base along dorsal curve, apex horn-like, blunt, exterior brownish sericeous puberulent; corolla bright vermilion or scarlet, 10-12cm long, mouth of limb about 7cm across, lobes about 3cm long, obtuse, margins strongly crispate, orange-yellow; filaments about 5cm long, dull orange anthers arcuate, linear, very dark brown, 15mm long; style yellow, 8cm long, stigma reddish; capsule lanceolate, slightly compressed, 17-25 x 3.5-7cm.
Agricultural areas, natural forests, ruderal/disturbed.
The African tulip tree invades both abandoned agricultural land and closed forest; it invades natural ecosystems in the Cook Islands, Fiji, Guam, Hawai‘I, Samoa and Vanuatu. Although the African tulip tree favours moist and wet areas below 1000m, it grows upto 1,200m in French Polynesia.
The tulip tree does not tolerate frost and demands full sun for fast growth and best flowering. The biggest trees grow in moist sheltered ravines. This species loves rich soil, but puts up with just about anything with a little fertility to it, including limerock. It will survive a bit of salinity.
The African tulip tree invades agricultural areas, forest plantations and natural ecosystems, smothering other trees and crops as it grows becoming the prevailing tree in these areas. In Hawaii, there are major infestations tucked away in almost every rainforest valley along the northern and eastern slopes of Kaua’I, O’ahu, and East Maui (Smith, Hawai‘ian Alien Plant Studies).
Native range: West Africa.
Known introduced range: American Samoa, Commonwealth of the Northern Mariana Islands, Cook Islands, Federated States of Micronesia, Fiji, French Polynesia, Galapagos Islands, Guam, Hawai‘i, Nauru, Malaysia, Marshall Islands, Niue, Palau, Samoa, Tonga, Vanuatu, Wallis and Futuna Islands, and Australia. Reported present on Christmas Island, Australia.
Preventative measures: A Risk Assessment of Spathodea campanulata for Haaii and other Pacific Islands was prepared with minor modifications for use in Pacific islands. The result is a high score of 14 and a recommendation of: “Likely to cause significant ecological or economic harm in Hawai‘I and on other Pacific Islands as determined by a high WRA score, which is based on published sources describing species biology and behaviour in Hawai‘I and/or other parts of the world.”