Erigeron karvinskianus DC., Asteraceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 11 (Go to the risk assessment)

Common name(s): [more details]

Chinese: jia le bi fei peng

English: Karwinsky's fleabane, Mexican daisy, Mexican fleabane, Santa Barbera daisy, bony-tip fleabane, daisy, daisy fleabane, seaside daisy

French: mère de famille nombreuse, marguerite folle, marguerite marron, pâquerette

Spanish: manzanilla silvestre

Habit:  herb

Description:  "Herbs, short-lived perennial, caespitose, [10-] 15-40+ [-100] cm tall; caudex short, simple or few branched, taprooted. Stems creeping or prostrate to ascending or erect, sometimes rooting at nodes, branched upward, sometimes with axillary leaf tufts, sparsely strigose to glabrate, eglandular. Leaves: basal and lower usually withered at anthesis, petiolate, petiole narrowly winged, blade elliptic or obovate; cauline shortly petiolate, elliptic to obovate or oblanceolate, 1-4 x 0.3-1.4 cm, even sized, surfaces sparsely strigose to glabrate, eglandular, base attenuate to cuneate, margin 2-4-lobed or entire, slightly revolute, strigose, apex acute or acuminate, mucronulate. Capitula 1 or 2 [-5] at ends of upper branches, 5-7 x 10-13 mm. Involucre campanulate; phyllaries 3- or 4-seriate, membranous, linear to lanceolate, 1.5-3.3 x 0.3-0.6 mm, sparsely strigose, apex acuminate, outer slightly shorter, green along midvein, inner margin narrowly scarious, erose. Ray florets female, 1- or 2-seriate, 45-80, 6-8 mm, tube 1-1.5 mm, lamina flat or slightly coiling, white, sometimes pinkish upon drying, linear, ca. 5 x 0.6 mm, 2-denticulate at apex, glabrous; disk florets bisexual, yellow, narrowly funnelform, tube ca. 2 mm, sparsely hairy, veins orange, lobes glabrous, apex papillate. Achenes oblong, flattened, ca. 0.8 mm (immature), sparsely strigose, 2-veined. Pappus 2-seriate, outer of short setae, inner bristles 15-27, ca. 2.5 mm"  (Flora of China online).

"Sprawling perennial herbs usually forming dense clumps; stems numerous, decumbent to weakly erect, slender, usually 1-3 dm long, branched, glabrate to sparsely pubescent.  Leaves linear to elliptic, entire to dentate or shallowly lobed, the lower ones often oblanceolate and 3-lobed, 1-4 cm long, 0.1-l cm wide.  Heads solitary, 4-9 mm in diameter; involucral bracts in 3 series, linear, 3-6 mm long; ray florets 75-100 or more per head, rays white, becoming pink with age, 9-10 mm long; disk florets numerous, corollas yellow.  Achenes pale brown, ca. 1 mm long"  (Wagner et al., 1999; pp. 315, 1860).

Description from the Flora of North America online.

Habitat/ecology:  Grows on cliff faces, disturbed locations in moderately wet areas.  A common garden plant. "Reproduces and spreads rapidly to form dense mats, can grow in almost any open habitat, including watercourses. Crowds out and displaces ground level plants, creating a virtual monoculture"  (Weeds of Blue Mountains bushland).

In Hawai‘i, "naturalized and sometimes locally common in moderately wet areas, ca. 300-1,300 m"  (Wagner et al., 1999; p. 315); "forming mats on forest floors, smothering low-growing natives"  (Motooka et al., 2003).  In New Zealand, "usually on banks or cliffs in waste places, forest margins, streamsides, or scrubland" (Webb et al., 1988, p. 192).

Propagation:  "Seeds are dispersed by wind and water, stems layer, broken roots and rhizomes regrow. Often sold on garden stalls; often dumped in bushland"  (Weeds of Blue Mountains bushland).

Native range:  Neotropics, Mexico to Venezuela, Chile and the Antilles (Wagner et al., 1999; p. 315).

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) Norfolk Islands	Norfolk Island	introduced invasive	Orchard, Anthony E., ed. (1994) (p. 8) "A native of Mexico, frequently naturalised as a garden escape with a tendency to weediness". Voucher cited: W.R. Sykes NI 467 (CHR)
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive cultivated	Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive cultivated	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (pp. 482, 528, 553) Voucher cited: Danton I(5/206)1551. "En RC, representa además un riesgo genético potencial para el endémico E. fernandezianus (Colla) Solbrig. La vimos cultivada en pocos jardines del pueblo de San Juan Bautista, pero su vigor y la facilidad con la cual se naturaliza deben, con el tiempo, dar a temer lo peor".
Cook Islands Southern Cook Islands	Rarotonga Island	cultivated	Sykes, Bill (year unknown)
Fiji Fiji Islands	Viti Levu Island	introduced cultivated	Smith, Albert C. (1991) (p. 305) Vouchers cited: DA 16438, DA 16091
Fiji Fiji Islands	Viti Levu Island		Bishop Museum (Honolulu) (1969) (voucher ID: BISH 34216) Taxon name on voucher: Erigeron karvinskianus DC.
Fiji Fiji Islands	Viti Levu Island		Bishop Museum (Honolulu) (1969) (voucher ID: BISH 34217) Taxon name on voucher: Erigeron karvinskianus DC.
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 315)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 315)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 315)
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Hughes, Guy D'Oyly (1995) (p. 2) Voucher cited: Hughes 36 (BISH) Sparingly naturalized in wet montane forest and along stream beds to at least 750 m elevation.
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 315) Voucher cited: Forbes 1700.0 (BISH)

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)	New South Wales	introduced invasive	Harley, Barbara (2009)
Australia Australia (continental)	Australia (continental)	introduced invasive cultivated	Csurhes, S./Edwards, R. (1998) (p. 159)
Central America Central America (Pacific rim)	Costa Rica (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	El Salvador (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Guatemala (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Honduras (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Panama (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
China China	China (People's Republic of)	introduced invasive cultivated	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Hillsides, escaped from cultivation; ca. 700 m.
China China	Hong Kong	introduced invasive	Wu, Te-lin (2001) (p. 281) In wasteland.
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 190)
Mexico Mexico	Mexico (United Mexican States)	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. 192)
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
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)
United States (west coast) United States (west coast states)	USA (California)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
United States (west coast) United States (west coast states)	USA (Washington)	introduced	U.S. Dept. Agr., Nat. Res. Cons. 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	Csurhes, S./Edwards, R. (1998) (p. 159)
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	Lavergne, Christophe (2006) "Très envahissant"
La Réunion (France) La Réunion Island	La Réunion Island	introduced invasive	Baret, Stephane/Rouget, Mathieu/Richardson, David M./Lavergne, Christophe/Egoh, Benis/Dupont, Joel/Strasberg, Dominique (2006) (p. 758)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
Seychelles Seychelles Islands	Seychelles Islands	introduced	Invasive Species Specialist Group (2017)

Comments:  A major problem on Kauai, Hawai‘i; spreading elsewhere. A serious weed on La Réunion.

Control: 

Physical:  "Dig out small spots: Avoid any unnecessary soil disturbance, Leave on site to rot down. plant material carefully. If seed is present, dispose of all plant material at a refuse transfer centre or burn it"  (Weedbusters New Zealand).

Chemical" "Sensitive to hormone type herbicides 2,4-D, dicamba and triclopyr and to soil-applied hexazinone and tebuthiuron" (Motooka et al., 2003).

"1. Spray: clopyralid (1ml/L). Selective.  2. Spray: glyphosate (10ml/L + penetrant in winter) or metsulferon-methyl 600g/kg (2g/10L + penetrant (knapsack) or 15g/100 L + penetrant (spraygun))"  (Weedbusters New Zealand).