Cortaderia selloana (Schult. & Schult.f) Aschers. & Graebner, Poaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results: 

Reject, score: 24 (Go to the risk assessment (Australia))
High risk, score: 24 (Go to the risk assessment (Pacific))

Other Latin names:  Arundo selloana Schult. & Schult. f.; Cortaderia argentea (Nees) Stapf

Common name(s): [more details]

Chinese: pu wei

English: Uruguayan pampas grass, pampas grass, silver pampas grass

French: herbe de la Pampa

Habit:  grass

Description:  "Robust, tussock grass up to 3.5 m in diameter; flowering stalks up to 4 m high.  Leaves:  Grayish- or bluish-green, up to 1800 mm long x 10 mm wide, reflexed, tips narrowly tapering, bristle-like, blade often v-shaped in cross section, margins rough, somewhat cutting; leaves mostly basal to two-thirds of the height of the flowing stalks. Inflorescence:  Silvery-white to pink or mauve, stiffly branching, feathery, 400-700 mm long.  Fruits:  Seeds, falling from old inflorescence which then appears white"  (Henderson, 1995; p. 12).

"Grande herbacée pérenne en touffe épaisse (« tussock-forming grass » en anglais) atteignant 3,5 m de diamètre, reconnaissable par ses longues feuilles et ses inflorescences dressées « en plumeau » de couleur blanche à rose sur des tiges de 3 à 4 m de hauteur" (Meyer, 2008; p. 23).

Habitat/ecology:  "Subhumid and semi-arid subtropical regions in open sunny places receiving added moisture, becoming naturalized as a weed in damp places, depressions, along stream banks, the margins of mangrove swamps and, in particular, disturbed areas associated with roads, pipeline cuts and walking trails in forest areas and waste places."  (Parsons and Cuthbertson, 1992; pp. 100-102)  It produces large amounts of flammable material, increasing fire risk.

In New Caledonia, "parfois planté dans les jardins" (MacKee, 1994; p. 58). In Australia, "it has naturalised in several vegetation communities including dry coastal plains, heathlands, riparian areas, wetlands, tuart forests, eculyptus forests and less frequently in grasslands (Swarbrick & Skarratt, 1994, cited in Csurhes & Edwards, 1998; p. 152).

"Elles colonisent les zones humides (bords de rivière, de marécages et de mangroves), les dunes et les falaises maritimes, et les zones perturbées (bords de route, sentiers, zones abondonnées)" (Meyer, 2008; p. 23).

Propagation:  Seed, wind-dispersed (Csurhes & Edwards, 1998; p. 152). "Leurs graines peuvent être dispersées par le vent à plus de 25 km de distance" (Meyer, 2008; p. 23).

Native range:  Argentina, Brazil, Chile, Uruguay; cultivated and naturalized elsewhere (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Chile (offshore islands) Rapa Nui (Easter) Island	Rapa Nui (Easter) Island (Isla de Pasqua)	introduced invasive cultivated	Meyer, Jean-Yves (2008) (pp. 22, 28) "Lors de cette mission, nous l’avons observé très abondante sur la falaise maritime de Tongariki où elle aurait été introduite pour lutter contre l’érosion du sol (Ignacio Espina, CONAF, comm. pers. 2008), très marquée dans ce site. Environ un millier de touffes (fertiles ou juvéniles) a été dénombré sur une surface d’environ 1 à 2 hectares contre « près d’une centaine » selon J.-F. Butaud (2005). Certaines touffes, accessibles sur pentes douces, sont broutées par les animaux herbivores. D’autres sont accrochées en bordures de falaise et quasiment inaccessibles (face au Motu Marotiri), ce qui exclue une éradication de cette espèce à Rapa Nui. Nous avons vu d’autres touffes dans le village de Hanga Roa et au cratère Rano Raraku où elle avait déjà été signalée par Lefeuver et al. (2005)" (Meyer, 2008; p. 23).
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. 479, 525, 552) Voucher cited: Danton I(5/186)1535. "En RC, se encuentra en varios sitios del pueblo de San Juan Bautista, en los jardines como fuera de ellos".
Cook Islands Southern Cook Islands	Rarotonga Island	cultivated	McCormack, Gerald (2013)
French Polynesia Society Islands	Tahiti Island	introduced cultivated	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Cultivée
French Polynesia Austral (Tubuai) Islands	Rapa Island	introduced cultivated	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Cultivée
French Polynesia Austral (Tubuai) Islands	Rurutu Island	introduced cultivated	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Cultivée
French Polynesia Austral (Tubuai) Islands	Tubuai Island	introduced cultivated	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Cultivée
State of Hawaii Hawaiian Islands	Hawaiian Islands	introduced cultivated	Staples, George W./Herbst, Derral/Imada, Clyde T. (2000) (p. 27)
State of Hawaii Hawaiian Islands	Kaua‘i Island	cultivated	Starr, Forest/Starr, Kim (year unknown)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive cultivated	Frohlich, Danielle/Lau, Alex (2010) (p. 15) Voucher cited: D. Clark 01 (BISH)
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced cultivated	MacKee, H. S. (1994) (p. 58) Voucher cited: MacKee 34892
New Zealand (offshore islands) Kermadec Islands	Raoul Island	introduced invasive cultivated	Sykes, W. R./West, C. J. (1996) (p. 452) Eradicated

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	National Herbarium of New South Wales (2013) Naturalised
Australia Australia (continental)	Australia (continental)	introduced invasive	National Herbarium of New South Wales (2013) South Australia, Tasmania, Victoria, Western Australia Naturalised
Australia Australia (continental)	Queensland	introduced invasive cultivated	Csurhes, S./Edwards, R. (1998) (p. 152)
Central America Central America (Pacific rim)	Costa Rica (Republic of)	introduced cultivated	U.S. Dept. Agr., Agr. Res. Serv. (2013)
China China	China (People's Republic of)	introduced cultivated	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Cultivated. Jiangsu.
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 192)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Owen, S. J. (1997)
New Zealand New Zealand	New Zealand (country)	introduced invasive cultivated	Edgar, E./Connor, H. (2000) (p. 497) "Widespread on roadsides, waste places, scrubland, and of more recent times in plantation pine forests; sea level to 800 m".
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Taiwan Taiwan Island	Taiwan Island	introduced cultivated	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Cultivated
United States (west coast) United States (west coast states)	USA (Oregon)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
United States (west coast) United States (west coast states)	USA (California)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
United States (west coast) United States (west coast states)	USA (Washington)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized

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 cultivated	Lavergne, Christophe (2006) "Cultivé/±envahissant"

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)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Alabama, Arizona, Georgia, Louisiana, New Mexico, South Carolina Naturalized

Comments:  A problem species in Australia and New Zealand. On New Zealand noxious weed list and banned from sale in that country.

See also Cortaderia jubata.

Control:  See also Gosling et al., 2000. and Popay et al., 2003.

Physical: Individual plants may be dug out, but all rhizomes must be removed.  "Dig or grub out seedlings or small plants. Chainsaw small plants and remove sizeable plants by bulldozer. Compost or Leave on site to rot down. the foliage. Burn or bury any flowerheads"  (Weedbusters New Zealand).

"En l’absence de moyen de lutte biologique et en raison du relief accidenté (pentes fortes) et de la proximité de la mer, seule la lutte manuelle est envisageable (coupe et arrachage des rhizomes). La perturbation du sol (lutte mécanique par déracinage des touffes) peut favoriser la ré-infestation des sites par germination des graines" (Meyer, 2008; p. 23).

Chemical: Treat with herbicide. Glyphosate may be used (see Parsons and Cuthbertson, 1992; pp. 100-102). 

"1. Weed wipe (all year round): glyphosate (200ml/L + penetrant).  2. Spray: Gallant (150ml/10l + crop oil) for most sites or glyphosate (100ml/10L + penetrant) for very dense sites . Use a marker dye to avoid wastage and a foaming agent to help prevent spray drift. Leave the plants in the ground until the roots have died off. Follow up as needed, but do not reapply herbicide too soon after the initial treatment - wait until the plant actively begins growing again"  (Weedbusters New Zealand).

"Un traitement chimique par pulvérisation des feuilles avec un herbicide (glyphosate, hexazinone) n’est possible qu’en dehors des zones humides" (Meyer, 2008; p. 23).