Perennial herb up to 1,5-3 m, rhizomatous, with yellow fragrant flowers and arranged in upright inflorescences.
Scientific name: Hedychium gardnerianum Sheppard ex Ker Gawl.
Common names: kahili ginger, kahila garland-lily, wild ginger
Status in Portugal: invasive species (listed in the Plano regional de erradicação e controlo de espécies de flora invasora em áreas sensíveis)
Risk Assessment score: (in development)
Synonymy: Gamochilus speciosus T. Lestib., Hedychium pallidium Regel, Hedychium gardnerianum var. pallidium Regel
Last update: 11/07/2014
How to recognise it
Fruits: capsules up to 1,5 cm long, orange-red within, containing numerous small seeds (5-6 mm), reddish and wrapped by an aril.
Flowering: July to October.
There are other species of Hedychium with which Hedychium gardnerianum may be mistaken with. Meanwhile, the colour of the flowers is a distinctive characteristic. In the Azores archipelago Hedychium coronarium J.Koenig is also invasive and is distinguished from Hedychium gardnerianum because it has white flowers.
Characteristics that aid invasion
It propagates by seed, producing a high number of seeds (each spike has, in mean, between 300 to 500 seeds) that are easily dispersed by wind, water and birds.
It also propagates vegetatively, by rhizomes.
Native distribution area
Asia (India, east from the Himalayas and Nepal).
Distribution in Portugal
Azores archipelago (all islands), Madeira archipelago (Madeira island).
Other places where the species is invasive
Europe (Spain, France), Pacific island (Micronesia, Cook, French Polynesia), North America (USA – Hawaii), Australia, New Zealand, South America (Caribbean), South Africa.
Preferential invasion environments
Along watercourses, roadsides, disturbed areas, forests and crop areas.
It also invades natural and semi-natural areas.
Impacts on ecossystems
The rapid growth leads to the formation of dense and impenetrable areas that inhibit the development of native vegetation.
High costs in the application of control methodologies.
On the banks of streams, when in large amounts, it may obstruct the drainage channels, consequently enhancing flood risk.
Very aromatic plant, being able to cause allergic reactions.
Controlling an invasive species demands a well-planned management, which includes the determination of the invaded area, identifying the causes of invasion, assessing the impacts, defining the intervention priorities, selecting the adequate control methodologies and their application. Afterwards it is fundamental to monitor the efficiency of the methodologies and recuperation of the intervened area as to perform, whenever necessary, the follow-up control.
The control methodologies used for Hedychium gardnerianum include:
Hand pulling: preferential methodology for small invaded areas. In more compacted substrates, hand pulling must be made during the rainy as to facilitate the removal of the root system. As much as possible, it should be guaranteed that there are no rhizomes and/or large rhizome fragments left in the ground because they regenerate very vigorously, diminishing the efficacy of this methodology.
Physical + chemical control
Cut stump method: methodology applicable to large invaded areas. The stems should be cut as close to the ground as possible and applied herbicide (active substance: metsulfuron-methyl) to the cut surface. Some authors refer that the sprouts are more sensitive to herbicide so, alternatively, the application of herbicide may be done when the sprouts achieve 50 to 60 cm high.
Foliar application of herbicide:methodology applicable to seedlings and young plants, up to 50 cm high. Spray with herbicide (active principle: metsulfuron-methyl) limiting the exposure to the target species. It should be made on the time of the plants’ greater growth.
The bacteria Ralstonia solanacearum (E. F. Smith) was tested in Hawaii, as a biological control agent of Hedychium gardnerianumbut, its use is not yet authorized.
This agent has not yet been tested in Portugal as to verify its safety relatively to native species, so its use has not yet constituted an alternative in our country.
Visit the webpage How to Control for additional and more detailed information about the correct application of these methodologies.
Anderson RC, Gardner DE (1999) An evaluation of the wilt-causing bacterium Ralstonia solanacearum as a potential biological control agent for the alien kahili ginger (Hedychium gardnerianum) in Hawaiian forests. Biological Control 15(2): 89-96.
CABI (2013) Hedychium gardnerianum. In: Invasive Species Compendium. CAB International, Wallingford, UK. Available: http://www.cabi.org/isc/ [Retrieved 06/01/2013].
Cordeiro N, L Silva (2003) Seed production and vegetative growth of Hedychium gardnerianum Ker-Gawler (Zingiberaceae) in São Miguel Island (Azores). Arquipélago, Life and Marine Sciences 20A: 31-36.
Csurhes S, Hannan-Jones M (2008) Pest plant risk assessment: Kahili ginger (Hedychium gardnerianum), White ginger (Hedychium coronarium), Yellow ginger (Hedychium flavescens). Biosecurity Queensland, Department of Primary Industries and Fisheries, Brisbane, 22pp.
DAISIE European Invasive Alien Species Gateway (2013) Hedychium gardnerianum. Available: http://www.europe-aliens.org/speciesFactsheet.do?speciesId=5464# [Retrieved 06/01/2013].
Global Invasive Species Database (2005) Hedychium gardnerianum. Available: http://www.issg.org/database/species/ecology.asp?si=57&fr=1&sts=sss&lang=EN [Retrieved 06/01/2013].
Govaerts R (2013) Hedychium gardnerianum Sheppard ex Ker Gawl. Facilitated by the Royal Botanic Gardens, Kew. Available: http://apps.kew.org/wcsp/ [Retrieved 06/01/2013].
Penacho ML, Amaral RS, Malveiro A, Machado CAS, Aranha JTM (2009) Controlo de invasoras Hedychium gardnerianum e Gunnera tinctoria em áreas florestais na ilha de S. Miguel – Açores. In: SPCF (ed) 6º Congresso Florestal Nacional: A floresta num mundo globalizado, Ponta Delgada, Açores, pp. 802-806.
PIER (Pacific Island Ecosystems at Risk) (2003) Hedychium gardnerianum. Available: http://www.hear.org/pier/species/hedychium_gardnerianum.htm [Retrieved 06/01/2013].
Silva L, Corvelo R, Moura M, Fernandes FM (2008) Hedychium gardnerianum Sheppard ex Ker Gawl. In: Silva L, Land EO, Luengo JLR (eds) Flora e fauna terrestre invasora na Macaronésia. Top 100 nos Açores, Madeira e Canárias. Arena, Ponta Delgada, pp. 217-220.
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