Mikania scandens (L.) Willd., Asteraceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Eupatorium scandens L.; Willoughbya scandens (L.) Kuntze

Common name(s): [more details]

English: climbing hempvine, climbing hempweed, louse-plaster

Spanish: guaco

Habit:  vine

Description:  "A herbaceous, perennial vine; stems branched, slightly four-angled, sparsely to densely pubescent; leaves opposite at swollen nodes, mostly triangular, 4 to 12 cm long, 2 to 7 cm wide, on a petiole 1 to 10 cm long, base sagittate, cordate, or hastate, tip acuminate, margins entire or with few teeth, surfaces glabrous, three- to seven-veined from base; flowers in small heads 5 to 7 mm long, crowded in round-topped, lateral and terminal, modified panicles (corymbs); involucral bracts four, linear-lanceolate, 4 to 5 mm long, attenuate, often purplish tinged, with an additional smaller bract; corolla pink, pale purplish, or rarely white; fruit an achene, oblong, 1.5 to 2.5 mm long, brownish black, five-angled; pappus of 30 to 35 bristles 2 to 4 mm long, white or sometimes purple"  (Holm et al., 1977; pp. 320-322).

"Glabrous vine with ovate to cordate or hastate leaves, acuminate, coarsely dentate or repand, 5-10 cm long, 2-5 cm wide; petioles slender, shorter than the blades; heads in terminal clusters; involucre about 5-6 mm long, bracts lanceolate-acuminate; corollas white; achenes resinous" (Stone, 1970).

The differences between M. scandens and M. micrantha are as follows:  "[T]he inflorescence is habitually looser and more paniculate in M. micrantha than in M. scandens; the inflorescence in M. scandens is mostly crowded with round-topped corymbs. The phyllaries (bracts) of the heads are acute in M. micrantha rather than attenuate as in M. scandens.  M. micrantha seems never to show the purplish coloration which is nearly always present in M. scandens.  Although the leaves vary greatly in contour both in M. scandens and in M. micrantha, they tend on the whole to be more sharply angled and triangular-sagittate or -hastate in M. scandens and more oval, cordate, and merely crenate in M. micrantha"  (Holm et al., 1977; p. 322).

Habitat/ecology:  "The plant is frequently found in woods, thickets, and swamps" in its native habitat (Holm et al., 1977; p. 322).

Propagation:  Seed dispersed by wind or in clothing or hair of animals. Vegetatively reproduces from broken stem fragments. Each node of the stem can produce roots.

Use as cattle feed, cover crop and a garden ornamental helps to spread the species.

Native range:  Temperate to subtropical eastern North America, the Bahamas and Mexico (Tamaulipas); also cultivated (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Aguijan (Agiguan, Aguihan) Island	introduced	Raulerson, L. (2006) (p. 68)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Rota Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 289)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Tinian Island	introduced	Raulerson, L. (2006) (p. 68)
Commonwealth of the Northern Mariana Islands (US) Saipan	Saipan Island	introduced	Raulerson, L. (2006) (p. 68)
Federated States of Micronesia Kosrae Island	Kosrae Island	introduced invasive	Josekutty, P. C./Wakuk, E. E./Joseph, M. J. (2002) (p. 63) See also Mikania micrantha. Possible missidentification?
Guam Guam Island	Guam Island	introduced invasive	Stone, Benjamin C. (1970) (p. 581) Vouchers cited: Stone 3995 (GUAM), Stone 4481 (GUAM), Stone 4903 (GUAM)
Guam Guam Island	Guam Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 289)
New Caledonia Îles Loyauté (Loyalte Islands)	Île Lifou	introduced	MacKee, H. S. (1994) (p. 36) Voucher cited: McPherson 6618
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced	MacKee, H. S. (1994) (p. 36) Vouchers cited: Uhe 1036 (NOU), Veillon 238 (NOU), MacKee 15179, MacKee 33276
Papua New Guinea Bismarck Archipelago	Bismarck Archipelago		Peekel, P. G. [translated by E. E. Henty] (1984) (p. 557) Common at bush margins.
Philippines Philippine Islands	Philippine Islands	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 322)
Philippines Philippine Islands	Philippine Islands	introduced invasive	Merrill, Elmer D. (1923) (p. 598) Often common in thickets at low and medium altitudes, ascending to 1,600 m.

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Indonesia Indonesia	Indonesia (Republic of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 322)
Malaysia Malaysia	Malaysia (country of)	introduced invasive	Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 322)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013) Tamaulipas

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
British Indian Ocean Territory Chagos Archipelago	Diego Garcia Island		Stoddart, D. R./Taylor, J. D., eds. (1971) (p. 159) A later publication (Topp, 1988) identifies this species as Mikania micrantha. Vouchers cited: Rhyne 616 (US), Stoddart 885 (K), Stoddart 793 (K, US)
British Indian Ocean Territory Chagos Archipelago	Diego Garcia Island	introduced invasive	Whistler, W. Arthur (1996) (p. 26) Apparently previously reported as Mikania micrantha.
British Indian Ocean Territory Chagos Archipelago	Diego Garcia Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1995) (voucher ID: PTBG 37881) Taxon name on voucher: Mikania scandens (L.) Willd.
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 237)

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)	United States (other states)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (continental except west coast) United States (other states)	USA (Florida)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

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

Control:  If you know of control methods for Mikania scandens, please let us know.