Taxonomic name: Melastoma candidum D. Don
Synonyms: Melastoma septemnervium
Common names: Asian melastome (English), Indian rhododendron (English-Hawaii), Malabar melastome (English-Hawaii)
Organism type: shrub Melastoma candidum (Asian melastome) is an invasive shrub that can spread rapidly and may form dense monotypic thickets in a variety of habitats such as: open land, grassland, shrubland and native forest. It originates from southeast Asia and was introduced to Hawaii as an ornamental shrub. All species of the genus Melastoma have a notoriously weedy history and noxious weed status but are still cultivated in Hawaii and elsewhere. Description
Melastoma candidum are "Erect shrubs or small trees 1.5-5m tall, branches and petioles are densely covered with a mixture of short, appressed, laciniate scales 0.5-1mm long and longer lanceolate scales 1.5-5mm long. Leaves elliptic to elliptic-ovate, 4-11cm long, 1.3-4cm wide, 5(-7) nerved, upper surface strigose to scabrous, lower surface sericeous but with a mixture of scales on the nerves like those of the young branches, margins entire, apex acute, base obtuse to rounded, petioles 5-12mm long. Inflorescenses 2-7 flowered, pedicels 10-12mm long in fruit, bracts and bracteoles elliptic, lanceolate, or ovate, 1-2.2cm long, 0.5-1.3cm wide, early deciduous; hypanthium densely covered with imbricate, lanceolate, ciliolate scales; calyx 5-lobed, triangular-lanceolate, 0.7-2cm long; petals usually 5, pink, 2.5-3.2cm long, 1.5-2.3cm wide; anthers of larger stamens 10-11mm long, anthers of smaller stamens 8.5-10mm long. Berries 5-celled, 10-15mm long." (Wagner et al., 1999 in Starr et al. 2003) Similar Species
Melastoma malabathricum, Melastoma sanguineum, Tibouchina urvilleana
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Occurs in:
natural forests, range/grasslands, ruderal/disturbed, scrub/shrublands, wetlands Habitat description
Melastoma candidum grows in light forests, clearings, and grass lands, or on rocky slopes from sea level to 1,500m elevation (Starr et al. 2003). It favours mesic to wet areas and bog margin habitats in Hawaii (Wagner et al. 1999 in PIER 2006). General impacts
Melastoma candidum can spread rapidly and smother to death vegetation that stand in its way (Degener 1973 in Starr et al.). Both M. candidum and the related similar species M. sanguineum form dense monotypic thickets up to 2m tall (Starr et al. 2003). Uses
Melastoma spp. are introduced through the horticulture trade and are still cultivated as ornamental shrubs in Hawaii and elsewhere (Starr et al. 2003). Melastoma candidum is also a Chinese medicinal herb of Hong Kong (USDA-GRIN 2006). Notes
Some Tibouchina species may be confused as Melastoma species (Starr et al. 2003). Geographical range
Native range: Melastoma candidum is native to Vietnam, southern China, Philippines, Taiwan, Ryukyu Islands, and southern Japan (Starr et al. 2003).
Known introduced range: Hawaii (PIER 2006). Introduction pathways to new locations
For ornamental purposes: Melastoma spp. are spread long distance by humans in the horticulture trade and are still cultivated as an ornamental shrub in Hawaii and elsewhere (Starr et al. 2003).
Horticulture:
Transportation of habitat material: Asian melastome can disperse accidentally as contaminants on hapu'u ferns or hapu'u mulch that is harvested from the wild forests of Hawai'i Island (Starr et al. 2003).
Local dispersal methods
Garden escape/garden waste: In Hawaii, Asian melastome has escaped from cultivation and is now locally abundant and invasive in mesic to wet areas, windward areas, and bog margins on Kauai, Oahu, and Hawaii from sea level up to about 900 m (2,952 ft) (Starr et al. 2003).
Natural dispersal (local): Asian melastome can be pollinated by bees and spread by fruit eating birds and possibly other mammals (Smith 1999 in Starr et al. 2003). Management information
Preventative measures: A Risk Assessment of Melastoma candidum for Hawaii and other Pacific islands was prepared by Dr. Curtis Daehler (UH Botany) with funding from the Kaulunani Urban Forestry Program and US Forest Service. The alien plant screening system is derived from Pheloung et al. (1999) with minor modifications for use in Pacific islands (Daehler et al. 2004). The result is a score of 13 and a recommendation of: "Reject the plant for import (Australia) or species likely to be of high risk (Pacific)."Chemical: Asian melastome is "sensitive to hormone type herbicides 2,4-D, dicamba and triclopyr at 1 lb/acre, and to metsulfuron at 0.45 oz/acre. It is sensitive to basal bark and stump bark applications of 2,4-D and triclopyr at 4% in diesel." (Motooka et al., 2002).
Cut at the base of the plant and treat with a herbicide. Cut material should be disposed off properly.
Ester formulations of triclopyr may be mixed in oil at 20% concentration or more and applied as in horizontal or vertical streaks on the basal bark to kill stumps (Motooka et al., 2002). These methods will cause less effects on native species that coexist with the target (Starr et al. 2003).
Soluble herbicide triclopyr can be drizzled over weeds at the appropriate concentration. However it is uncertain whether foliar spray applications would work, and this would have the most non-target effects and may be unsitely in a garden situation (Starr et al. 2003). Biological: Several moth species (Lepidoptera) have been introduced as biological control agents for M. candidum in Hawaii (Teramoto and Heu 2000 in Starr et al. 2003). Physical: Small, cultivated specimens can be pulled up by hand (Starr et al. 2003). Preventative measures: All species in the genus Melastoma are listed as Hawaii state noxious weeds, making it illegal to possess, sell, and propagate them in Hawaii. The public could be discouraged from using any plants in the family Melastomataceae. The public could also be discouraged from planting hapu'u ferns (Cibotium spp.) or use hapu'u mulch that is harvested from the wild forests of Hawaii as they often harbor noxious weed species such as Melastoma spp. (Starr et al. 2003). Reproduction
Melastoma candidum produce berry-like fruits that are dispersed by frugivorous birds (Smith 1985 in PIER 2006). "Many plants in the family Melastomataceae are pollinated by bees. Melastoma spp. can be propagated from seeds." (Meyer 2000 in Starr et al. 2003) Lifecycle stages
Perennial (USDA-NRCS 2006) Reviewed by: Forest Starr and Kim Starr, Botanical Research Associates United States Geological Survey Biological Resources Division Makawao, Maui, Hawaii USA
Compiled by: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG)
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Last Modified: Wednesday, 6 December 2006
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