Persicaria capitata (Buch.-Ham. ex D.Don) Masamune, Polygonaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 13 (Go to the risk assessment)

Other Latin names:  Polygonum capitatum Buch.-ham. ex D. Don

Common name(s): [more details]

Chinese: tou hua liao

English: pinkhead knotweed, pinkhead smartweed

French: couvre-sol, herbe corail

Habit:  herb

Description:  "Mat-forming perennial herbs from a stout woody root; stems prostrate, sometimes rooting at the nodes, 0.5-3.5 dm long, many-branched.  Leaves with a conspicuous purple V-shaped band, occasionally also tinged red or purple, elliptic-ovate to elliptic, 1-4 (-6.2) cm long, 0.6-2.5 (-3.3) cm wide, both surfaces sparsely strigillose, margins glandular ciliate, petioles 1-4 mm long, glandular villous, usually with an auricle that clasps the stem, ocreae reddish brown, tubular, to 6-10 mm long, glandular hirsute, apex glandular ciliate.  Flowers in subglobose or capitate spikes, these 1 to several at the ends of the branches, peduncles with purple glandular hairs; tepals pink, 2-2.5 mm long.  Nuts dark reddish brown, trigonous, ca. 2 mm long, apex beaked, the surface somewhat striate, glossy"  (Wagner et al., 1999; p. 1063).

Habitat/ecology:  In Hawai‘i, "naturalized in wet forest, open lava fields, and along roadsides, 600-1,770 m" (Wagner et al., 1999; p. 1063).

Propagation:  Seed

Native range:  Himalayas and western China, widely cultivated (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
Guam Guam Island	Guam Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 66)
Guam Guam Island	Guam Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1965) (voucher ID: PTBG 23180) Taxon name on voucher: Persicaria capitata
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1060, 1063, 1888)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1060, 1063, 1888)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Oppenheimer, Hank L./Bartlett, Randal T. (2002) (p. 11) East Maui. Voucher cited: Oppenheimer H70069 (BISH)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1060, 1063, 1888)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive cultivated	Frohlich, Danielle/Lau, Alex (2010) (p. 15) Voucher cited: OED 200807180 (BISH)

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) "Mountain slopes, shaded places in valleys; 600-3500 m".
China China	Hong Kong	introduced cultivated	Wu, Te-lin (2001) (p. 82) Cultivated in gardens.
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 181)
Malaysia Malaysia	Malaysia (country of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 972) "Cultivation escape, steep banks, crevices of walls and amongst rocks near habitations, also less modified habitats such as coastal cliffs".
Singapore Singapore	Singapore (Republic of)	introduced cultivated	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 68) Cultivated only
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)

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	MacDonald, I. A. W./Thebaud, C./Strahm, W. A./Strasberg, D. (1991) (pp. 51-61)
La Réunion (France) La Réunion Island	La Réunion Island	introduced invasive cultivated	Lavergne, Christophe (2006) "Cultivé/envahissant"

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