Verbena bonariensis L., Verbenaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

English: South American vervain, purple top, purple-top vervain, purpletop, purpletop vervain, tall verbena, verbena

Fijian: sekara, vunikuta

Niuean: momili vao

Habit:  herb

Description:  "Coarse, erect annual or perennial herbs 3-20 dm tall, sometimes somewhat woody toward base; stems erect, conspicuously quadrangular, scabrous to hispid.  Leaves decussate, lanceolate to oblong-lanceolate, 4.5-13 cm long, 0.6-2 cm wide, upper surface rugose and hirtellous, lower surface spreading pubescent, both surfaces occasionally hirsute or scabrous, margins somewhat revolute, unequally serrate, entire toward base, apex acute, base cordate, sessile and somewhat clasping the stem.  Flowers numerous in 4-10 spikes 1-2 (-5) cm long, these in a paniculate arrangement, bracts lanceolate, as long as or slightly longer than calyx; calyx ca. 3 mm long, hispidulous, not glandular pubescent; corolla blue, violet, lavender, or purple, the tube ca. 6-7 mm long" (Wagner et al., 1999; pp. 1325, 1896).

Habitat/ecology:  "Grass- and woodland, riparian habitats, forest edges, disturbed sites.  Were invasive, this plant often forms dense swards that crowd out native plants.  It establishes well in disturbed sites and may persist"  (Weber, 2003; p. 450).

In Fiji, "sometimes grown in gardens as an ornamental but is more often considered a weed in settlements and waste places from near sea level to about 850 m" (Smith, 1991; pp. 166-167). In New Guinea, "a weed of waste land and pastures; not aggressive, but persistent, and sometimes prominent after prolonged heavy grazing. At altitudes from 1000 to 2500 m" (Henty & Pritchard, 1975; p. 161).

Propagation:  Seed.  "The long-lived seeds are accumulated in a soil seed bank"  (Weber, 2003; p. 450).

Native range:  Brazil and Bolivia to Argentina and Chile, now widespread in South America and many other parts of the world (Wagner et al., 1999; p. 1325).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia (Pacific offshore islands) Lord Howe Island	Lord Howe Island	introduced	Pickard, J. (1984) (p. 208)
Australia (Pacific offshore islands) Norfolk Islands	Norfolk Island	introduced invasive	Orchard, Anthony E., ed. (1994) (p. 11) "Presumably introduced as a garden ornamental, now commonly naturalised and spreading on the Island". Voucher cited: W.R. Sykes NI 161 (CHR)
Fiji Fiji Islands	Viti Levu Island	introduced invasive cultivated	Smith, Albert C. (1991) (pp. 166-167) Vouchers cited: DA 2465, Meebold Aug. 1932, Vakaloloma & Lambel (CHR 307758)
French Polynesia Austral (Tubuai) Islands	Rapa Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2002) (voucher ID: PTBG 42103) Taxon name on voucher: Verbena bonariensis
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Lorence, David H./Flynn, Timothy W./Wagner, Warren L. (1995) (p. 55) Vouchers cited: T. Flynn & W.L. Wagner 3980 (BISH, MO, PTBG, US), W.L. Wagner & T. Flynn 6757 (BISH, PTBG, US) Probably introduced as a grass seed contaminant.
State of Hawaii Hawaiian Islands	Lāna‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1325) Voucher cited: Munro 352 (BISH)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1325) Voucher cited: Hobdy 2817 (BISH)
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1325)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Frohlich, Danielle/Lau, Alex (2008) (pp. 9-10) Voucher cited: K. Kawelo s.n. (BISH 727457). Plants removed by O‘ahu Invasive Species Committee.
New Caledonia New Caledonia	New Caledonia Islands		Swarbrick, John T. (1997) (p. 98)
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced invasive	Tassin, Jacques (2005)
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced	MacKee, H. S. (1994) (p. 140) Vouchers cited: Le Rat 330, Däniker 114, MacKee 7874, MacKee 36675, Koyama & al. 4238
New Caledonia New Caledonia Archipelago	Île des Pins (Isle of Pines)	introduced invasive	Tassin, Jacques (2005)
New Caledonia New Caledonia Archipelago	Île des Pins (Isle of Pines)	introduced	MacKee, H. S. (1994) (p. 140) Voucher cited: Germain s.n.
New Zealand (offshore islands) Kermadec Islands	Raoul Island	introduced invasive	Sykes, W. R. (1977) (pp. 150-151)
New Zealand (offshore islands) Kermadec Islands	Raoul Island	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 1277) "Roadsides, waste places in and around settlements, open and modified habitats".
Niue Niue	Niue Island	introduced	Sykes, W. R. (1970) (p. 215) Not common per Sykes. Voucher cited: CHR 169881
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	introduced invasive	Henty, E. E./Pritchard, G. H. (1975) (p. 161) Reported from several localities, at altitudes from 1000 to 2500 m.
Pitcairn Islands Pitcairn Islands	Pitcairn Island	introduced invasive	St. John, H. (1987) (p. 48) Vouchers cited: R. A. Young 8, St. John 14993, J. P. Chapin 947
Pitcairn Islands Pitcairn Islands	Pitcairn Island	introduced	Fosberg, F. R./Paulay, Gustav/Spencer, T./Oliver, Royce (1989) (p. 15) Voucher cited: Paulay, Spencer & Schuster 681 (US)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia Australia (continental)	Australia (continental)	introduced	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
China China	Hong Kong	introduced	Wu, Te-lin (2001) (p. 232)
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 188)
New Zealand New Zealand	New Zealand (country)	introduced invasive cultivated	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 1277) "Roadsides, waste places in and around settlements, open and modified habitats".
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Colombia	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Ecuador (Republic of) (continental)	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
Mascarene Islands Mascarene Islands (Mauritius, La Reunion, Rodrigues)	Mascarene Islands	introduced	Weber, Ewald (2003) (p. 450)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 378)

Control: 

Physical:  Hand pull or dig out seedlings and scattered plants.

Chemical:  Treat large stands with herbicide (Weber, 2003; p. 450).