Rhodomyrtus tomentosa (Aiton) Hassk., Myrtaceae

Click on an image for links to BIGGER PICTURES

Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 8 (Go to the risk assessment)

Common name(s): [more details]

Chinese: tao jin niang

English: Isenberg bush, downy myrtle, downy rose myrtle, hill guava, rhodomyrtus, rose myrtle

French: feijoarte-groseille, myrte-groseille

Spanish: guayabillo forastero

Habit:  shrub

Description:  "A large shrub to small twiggy tree, up to 10 feet high; older branches yellowish, fissured with loose bark. Leaves 2 to 3 inches long, 3-veined from the base, oval, obtuse to sharp pointed at the tip, densely gray or rarely yellowish-hairy beneath, entire, with wide leafstalk. Flowers 3/4 to 1 inch wide, solitary or two to three; petals tinged white outside with purplish-pink or all pink. Fruit purple, round, 3-celled, capped with persistent calyx lobes, about 1/2 inch wide, soft with double row of seeds in each cell, edible. Seeds triangular" (Haselwood, 1966; p. 282).

Habitat/ecology:  "Open forests, woodland, pineland.  This shrub is common in open sandy ground, sea shores, and riverbanks where native.  It is well adapted to dry and hot places, and tolerates saline soils.  It invades pineland in Florida and displaces the native understorey vegetation with dense and impenetrable, pure thickets.  Little is known on the ecology of this plant"  (Weber, 2003; p. 359).  This noxious evergreen shrub rarely grows above 3 m but forms dense thickets (Smith, 1985; p. 201). "Thrives in environments where annual rainfall exceeds 1200 mm.  A weed of pasture, rangeland and untended  areas. Forms impenetrable thickets" (Waterhouse & Mitchell, 1998; pp. 55-56).

In Hawai‘i, "cultivated and naturalized in disturbed mesic forest to wet forest, rearely bog margins, 200-640 m"  (Wagner et al., 1999; p. 972).

Propagation:  Produces large amounts of seed that are dispersed by frugivorous birds and possibly mammals  (Weber, 2003; p. 359).

Native range:  Southeast Asia, Malaysia, and the Philippines.

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
French Polynesia Society Islands	Raiatea (Havai) Island	introduced invasive	Meyer, Jean-Yves (2000) (p. 93) "Mesic/wet habitats"
French Polynesia Society Islands	Raiatea (Havai) Island	possibly introduced	Welsh, S. L. (1998) (p. 201) Vouchers cited: Whistler 4884, BRY 24865, BRY 26622
French Polynesia Society Islands	Raiatea (Havai) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Vouchers cited: J. Florence 10448 (PAP), J. Florence 10672 (PAP), J. Florence 11903 (PAP) Naturalisée, Menace pour la biodiversité
French Polynesia Society Islands	Raiatea (Havai) Island		Bishop Museum (Honolulu) (1990) (voucher ID: BISH 642901) Taxon name on voucher: Rhodomyrtus tomentosa (Aiton) Hassk.
French Polynesia Society Islands	Raiatea (Havai) Island		Bishop Museum (Honolulu) (1993) (voucher ID: BISH 658360) Taxon name on voucher: Rhodomyrtus tomentosa (Aiton) Hassk.
French Polynesia Society Islands	Raiatea (Havai) Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1981) (voucher ID: PTBG 37702) Taxon name on voucher: Rhodomyrtus tomentosa
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 972-973)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 972-973)
State of Hawaii Hawaiian Islands	Lāna‘i Island	introduced invasive cultivated	Staples, George W./Imada, Clyde T./Herbst, Derral R. (2002) (p. 13) Voucher cited: O. & I. Degener 28503 (BISH)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Starr, Forest/Starr, Kim (2013) (p. 35) East Maui. Voucher cited: Starr, Starr & Takeda 120319-02 (BISH)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 972-973)
Japan (offshore islands) Ogasawara (Bonin) Islands	Bonin (Ogasawara) Islands	introduced	Kato, Hidetoshi (2007)
Philippines Philippine Islands	Philippine Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Philippines Philippine Islands	Philippine Islands		Merrill, Elmer D. (1923) (p. 156) In thickets at low altitudes.

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Cambodia Cambodia	Cambodia (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
China China	China (People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
China China	Hong Kong	native	Wu, Te-lin (2001) (pp. 163-164)
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Malaysia Malaysia	Malaysia (country of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Singapore Singapore	Singapore (Republic of)	native	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 75) Common
Taiwan Taiwan Island	Taiwan Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Thailand Thailand	Thailand (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Vietnam Vietnam	Vietnam (Socialist Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
United States (continental except west coast) United States (other states)	USA (Florida)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)

Comments:  On the State of Hawai‘i noxious weed list.

A serious problem on Raiatea, French Polynesia (Meyer, 1998).

Planting of this species is prohibited in Miami-Dade County, Florida (U.S.) (Miami-Dade County Dept. of Planning and Zoning, 2010).

Control: 

Physical:  Hand pull or dig out seedlings and young plants. "Not grazed by cattle"  (Motooka et al., 2003).

Chemical:  Cut large plants and treat the stumps with herbicide.  "Sensitive to foliar applications of dicamba at 2 lb/acre and triclopyr at 2 lb/acre but requires follow-up treatments.  Sensitive to conventional basal bark applications of 2% triclopyr ester product and to 20% in very-low-volume basal bark applications.  In stump bark applications, 2% 2,4-D or triclopyr ester products in oil by conventional spraying or 20% triclopyr ester product in very-low-volume applications were effective.  Tolerates metsulfuron and soil-applied tebuthiuron"  (Motooka et al., 2003).