Hedychium coronarium
(white butterfly ginger lily)

H. coronarium is invasive in shallow water systems, along streams and in waterlogged areas in the tropics and subtropics. Once established, it is difficult to control because it reproduces vegetatively. Its attractive flowers make it a desirable ornamental plant.

H. coronarium is a native of the Himalayas and southern China (van Valkenburg and Bunyapraphatsara, 2001). It was cultivated in English glasshouses in the late 18th  century and in 1803 was noted as being “very rare” in Curtis’s Botanical Magazine (Csurhes and Hannan-Jones, 2008). It has been taken to many parts of the world and is a popular landscape and ornamental plant throughout Florida, the Gulf Coast, California, the Caribbean and tropical and subtropical areas worldwide. It is also grown in mild winter temperate regions of North America and Europe where it dies back in winter but re-emerges in spring.

Naturalised and invasive in Brazil, the species occurs in swamps in large areas of the country, along roadsides in the municipality of Teresópolis, Rio de Janeiro (Souza and Correia, 2007). The plant is thought to have been brought there by African slaves who used the leaves of this plant as mattresses. It is also found all along the coastline with high concentrations in the cocoa plantation areas of the states of Bahia and Espirito Santo (Kissmann, 1997).

This species was first recorded in Hawaii in 1888, introduced by Chinese immigrants as an ornamental and is now widely distributed and a serious invader in the wet habitats of the archipelago. There are major infestations above Nahiku and Wailau Valley (Maui), as well as Puna and Kohala Mountains (Big Island). It is not clear why white ginger infestations are confined to Maui and Big Island, as suitable habitat exists on other islands (Smith, 1998). It occurs in the mesic to wet areas of Kauai, Maui, Lanai and Oahu and Molakai (Motooka et al., 2003).

In Cuba, the plant has gone wild in the cool rainy mountains in Sierra del Rosario, Pinar del Rio Province in the west, Escambray Mountains in the centre of the island and in Sierra Maestra in the very west of it.

In Nairobi, Kenya, H. coronarium is invasive along streams.

In South Africa, it is a declared weed of forests, plantations, riverbanks and moist, shaded sites (Category 1 plants): “These are prohibited plants that will no longer be tolerated, neither in rural nor urban areas, except with the written permission of the executive officer or in an approved biocontrol reserve. These plants may no longer be planted or propagated, and all trade in their seeds, cuttings or other propagative material is prohibited. They may not be transported or be allowed to disperse”. First recorded from Kruger National Park in 1999 (Foxcroft et al., 2008).

It is ironic that whilst awareness of invasive Hedychium spp. including H. coronarium, is on the rise worldwide, the humid submontane forest ecosystems from which they originate are fast becoming the most threatened ecosystems in the world and a number of wild gingers are listed as endangered by the Botanical Survey of India (Soares and Barreto, 2008).

H. coronarium grows in humus-rich, shaded or semi-shaded areas subjected to waterlogging. It is usually found along water margins and in shallow water but is never totally submerged (Joly and Brandle, 1995). It can also occur on the edges of shaded secondary forests. It is found at altitudes from sea level to 2500 m (van Valkenburg and Bunyapraphatsara, 2001).

Under ideal growing conditions, H. coronarium can choke most other vegetation by forming dense colonies. In Brazil it is a weed in banana and cocoa plantations (Kissmann, 1997).

Physiology and Phenology

H. coronarium is a perennial plant which forms clones from rhizome buds. Flower development has been studied by Kirchoff (1997). The success of colonization and rapid proliferation of the species is partly due to its foliar architecture. H. coronarium can thrive in waterlogged soil and high light habitats. Only the youngest leaves are vertical and the number of stomata is higher on the abaxial face, with hypoderm, asymmetrical mesophyll and folding of the margins all of which appear to act as preventative measures against photoinhibition (Boeger et al., 2007).

Reproductive Biology

Reproduction is mainly vegetative, from parts of rhizomes, but also sexual. Spread by seeds is generally localized because the seeds are not produced in large numbers and are rarely displayed conspicuously (HEAR, 2004). However, the red aril that covers the seeds attracts a number of insects that may carry the seeds a short distance. H. coronarium does naturalize by seed in Hawaii and a recent survey showed it at altitudes as high as 2500 feet on east Maui. A spontaneous naturalizing hybrid between H. coronarium and H. gardnerianum has been found in Medeiros, Haleakala National Park Maui, Hawaii, which favours the simultaneous seed production of H. gardnerianum (P Bily, The Nature Conservancy, USA, personal communication, 2008). The flowers are zygomorphic, hermaphroditic and nectariferous and exhibit nocturnal anthesis, emitting a strong odour that can spread long distances. The staminodes attract floral visitors and the androecium is composed of a sole fertile stamen with pollen grains. The stigma is green, wet, concave and surrounded by uniform hairs. The species is self-incompatible, presenting low rates of fruit set and the flowering follows an annual pattern, showing asynchrony in the population level (Souza and Correia, 2007).

Environmental Requirements

H. coronarium can be found in tropical and subtropical regions. It favours waterlogged habitats with high temperatures all year round. The plants are susceptible to severe frost. As a cultivated plant it can live in upland gardens and even indoors. Partial sun to light shade is ideal but plants will tolerate considerable shade and even full sun if adequate moisture is available. Once established, it will tolerate seasonal droughts as well as more or less boggy conditions.

In Hawaii, the soilborne plant pathogenic bacterium Ralstonia solanacearum was isolated from a number of ginger species including H. coronarium. It causes a significant bacterial wilt disease and is spread naturally via soil water and root-root transmission, as well as artificially through wounds and agricultural practices.

A number of fungi have been recorded from Hedychium spp. and more than 20 fungi have been recorded from H. coronarium worldwide (Bussaban et al., 2002). A search of herbarium and fungal databases as well as recent National surveys in New Zealand and Brazil list the following:

Leafspots (Colletotrichum sp., Leptosphaeria sp., Mycosphaerella hedychii, Pestalotiopsis sp., Phoma sp.) from American Samoa; Cercospora apii, Mycosphaerella sp. from Venezuela; Alternaria sp., Cladosporium sp., Leptosphaeria sp. from the Caribbean and Cuba; Pestalotia microspora from Cuba; Cercospora hedychii from Hong Kong and Myanmar; Chalara aurea, Curvularia lunata var. aeria, Gonatophragmium mori, Pseudocercospora hedychii, Veronaea hedychii from Brazil; Macrophoma hedychii, Pestalotia funerea var. hedychii from Portugal; Pestalotia guepinii from the USA; Marasmius pseudobambusinus var. hawaiiensis, Rhizoctonia sp., Mycosphaerella hedychii, Hobsonia gigaspora, Phyllosticta sp. from Hawaii; as well as Bartalinia robillardoides, Fusarium oxyspermum, Drechlsera and a stem ascomycete from India.

Soares and Barreto (2008) also give a comprehensive review of the fungal pathogens found on H. coronarium in Brazil and evaluate their potential as biocontrol agents.

H. coronarium is listed as the host plant of a number of lepidopterans (Natural History Museum database, UK) including: several Caligo spp. (Nymphalidae) and Calpodes ethlius (Noctuid) from Brazil, Spodoptera litura (Noctuid) and Udaspes folus (Hesperiidae) from Hong Kong, and Jamides alecto from Japan and Taiwan.

H. coronarium is reported to be an alternative host to banana bunchy-top virus (BBTV) in Taiwan (Csurhes and Hannan-Jones, 2008). In Queensland, the BBTV vector banana black aphid, Pentalonia nigronervosa, is reported from H. coronarium (Geering and Thomas, 1997). However, attempts by DPI&F to inoculate H. coronarium with an Australian isolate of BBTV (BBTV-482) failed (Geering and Thomas, 1997), as did an attempt in India with an Indian isolate (Csurhes and Hannan-Jones, 2008). Geering and Thomas (1997) suggested that the difference in susceptibility of H. coronarium to BBTV could be explained by strains with different biological properties. Australian and Indian strains belong to South Pacific sequence group while those in Taiwan to the Asian Group (Karan et al., 1994). An alternative hypothesis put forward by Geering and Thomas was that there was variation in the presence of resistance genes to the virus in the populations of H. coronarium. Whatever the susceptibility of H. coronarium to BBTV in Queensland, it can still play a part in the epidemiology of BBTV by acting as a reservoir of the virus vector P. nigronervosa.

Environmental

• Amenity
• Landscape improvement

Fuels

• Fuelwood

General

• Botanical garden/zoo
• Capital accumulation
• Ritual uses
• Sociocultural value
• Souvenirs

Human food and beverage

• Flour/starch

Materials

• Oils

Medicinal, pharmaceutical

• Source of medicine/pharmaceutical
• Traditional/folklore

Ornamental

• Cut flower
• Propagation material
• Seed trade

Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Mechanical Control

Because this plant can regenerate from rhizomes, mechanical removal is often unsuccessful. Its adaptation to fire is unknown but unless the fire is intense enough to harm the rhizomes it will recover.

Chemical Control

Research in Panama showed that picloram combined with 2,4-D and sprayed onto plants 22 and 60 days after sprouting resulted in over 90% control of H. coronarium compared with 36% control using the cheaper farmers' practice of diesel plus 2,4-D (Hertentains et al., 1998). Single applications are not suitable because of regrowth from the rhizomes. In Hawaii, H. coronarium was found to be sensitive to foliar applications of picloram, very sensitive to metsulfuron and moderately susceptible to triclopyr (Motooka et al., 2003).

Biological control

A research project has been ongoing since 2008 to investigate the potential for classical biological control of invasive Hedychium species for a consortium of sponsors from New Zealand and Hawaii. Surveys to the native range in 2008-2010 revealed a large suite of natural enemies associated with H. coronarium, but the focus of the research will be on H. gardnerianum, which is the most pernicious of the invasive Hedychium complex. (D Djeddour, CABI E- UK, personal communication, 2011).

01/08/2008 Updated by:

Djamila Djeddour, CAB Europe - UK, Bakeham Lane, Egham, Surrey TW20 9TY, UK

07/07/13 Updated by:

Julissa Rojas-Sandoval, Department of Botany-Smithsonian NMNH, Washington DC, USA

Pedro Acevedo-Rodríguez, Department of Botany-Smithsonian NMNH, Washington DC, USA