Persicaria chinensis (L.) Nakai, Polygonaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 14 (Go to the risk assessment)

Other Latin names:  Polygonum chinense L.

Common name(s): [more details]

Chinese: huo tan mu

English: Chinese knotweed, red bush

French: liane rouge

Habit:  herb

Description:  "Perennial herbs or subshrubs; stems scandent or prostrate, with ascending lateral branches, usually glabrous. Leaves broadly ovate to ovate-oblong, (4-) 8-12 cm long, 3-6 cm wide, glabrous or with a few fleshy hairs on nerves of lower surface, apex acuminate, base truncate-cuneate, petioles 1.5-2 cm long, ocreae membranous, 10-20 mm long, glabrous, apex obliquely truncate. Flowers 10-20 in terminal, subglobose spikes, these cymose or paniculate, peduncles usually sparsely glandular pubescent; tepals white or rarely somewhat pinkish, 3-4 mm long, enlarging and becoming fleshy and dark purple or bluish in fruit. Nuts dull black, trigonous, 3-4 mm long" (Wagner et al., 1999; p. 1063).

Habitat/ecology:  In Hawai‘i, "sparingly naturalized in agricultural lands and disturbed areas, 60-520 m" (Wagner et al., 1999; p. 1063).  In Papua New Guinea (native), "in forest, particularly in natural clearings, and in regrowth, abandoned gardens and at roadsides, mostly at altitudes 1000-2500 m"  (Womersley, 1978; p. 234).

Propagation:  Seed

Native range:  Tropical and subtropical eastern Asia (Wagner et al., 1999; p. 1063).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1063, 1888) Voucher cited: Mikami s.n. (BISH) Sparingly naturalized.
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Imada, Clyde T./James, Shelly A./Kennedy, Barbara H. (2008) (p. 13) Voucher cited: C. Imada 2007-09 (BISH)
Papua New Guinea Bougainville Islands	Bougainville Island	native	Womersley, John S., ed. (1978) (p. 234)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	native	Womersley, John S., ed. (1978) (p. 234)
Philippines Philippine Islands	Philippine Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Philippines Philippine Islands	Philippine Islands		Merrill, Elmer D. (1923) (p. 122) In thickets and forests at medium and higher altitudes, 1,200 to 2,400 m.

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
China China	China (People's Republic of)	native	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) "Wet valleys, grassy slopes, mixed forests, thickets in valleys, mountain slopes; sea level to 3000 m".
China China	Hong Kong	native	Wu, Te-lin (2001) (p. 82)
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Japan Japan	Japan	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
North Korea North Korea	North Korea (Democratic People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South Korea South Korea	South Korea (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)	introduced invasive	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 68) Naturalised
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)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
La Réunion (France) La Réunion Island	La Réunion Island	introduced invasive	Lavergne, Christophe (2006) "Naturalisé/±envahissant".

Control:  If you know of control methods for Persicaria chinensis, please let us know.