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))

Common name(s): [more details]

English: pampas grass, silver pampas grass, Uruguayan 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:  South America

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Chile (Rapa Nui Island) 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).
Cook Islands Southern Cook Islands	Rarotonga Island	cultivated	McCormack, Gerald (2008)
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)
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)	Queensland	introduced invasive cultivated	Csurhes, S./Edwards, R. (1998) (p. 152)
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".

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"

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.

"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).

"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).

Additional information:
Report (PDF format) from US Geological Survey, Biological Resources Division, Haleakala Field Station, Hawaii "Plants of Hawaii".
Information on the Environment Bay of Plenty, New Zealand, web site.
Information from the Global Invasive Species Database.

Additional online information about Cortaderia selloana is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Cortaderia selloana as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Cortaderia selloana may be available from the Germplasm Resources Information Network (GRIN).

References:

Csurhes, S./Edwards, R. 1998. Potential environmental weeds in Australia: Candidate species for preventative control. Canberra, Australia. Biodiversity Group, Environment Australia. 208 pp.

Edgar, E./Connor, H. 2000. Flora of New Zealand, vol. V: Gramineae. Manaaki Whenua Press. .

Gosling, D. S./Shaw, W. B./Beadel, S. M. 2000. Review of control methods for pampas grasses in New Zealand. Department of Conservation, New Zealand. Science for Conservation 165.

Henderson, Lesley. 1995. Plant invaders of Southern Africa. Plant Protection Research Institute Handbook No. 5, Agriculture Research Council, ARC/LNR, Pretoria, South Africa. 177 pp.

Lavergne, Christophe. 2006. List des especes exotiques envahissantes a La Reunion. Unpublished manuscript (Excel file). .

MacKee, H. S. 1994. Catalogue des plantes introduites et cultivées en Nouvelle-Calédonie. Muséum National d'Histoire Naturelle, Paris, 164 p.

McCormack, Gerald. 2008. Cook Islands Biodiversity Database, Version 2007.2. Cook Islands Natural Heritage Trust, Rarotonga.

Meyer, Jean-Yves. 2008. Rapport de mission d'expertise a Rapa Nui du 02 au 11 Juin 2008: Plan d'action strategique pour lutter contre les plantes introduites envahissantes sur Rapa Nui (Île de pâques) [Strategic action plan to control invasive alien plants on Rapa Nui (Easter Island) [unpublished report]. Délégation à la Recherche, Ministère de l'Education, l'Enseignement supérieur et la Recherche, B.P. 20981 Papeete, Tahiti, Polynésie française. 62 pp. .

Owen, S. J. 1997. Ecological weeds on conservation land in New Zealand: A database. Working draft. Wellington, New Zealand. Department of Conservation.

Parsons, W. T./Cuthbertson, E. G. 1992. Noxious weeds of Australia. Inkata Press, Melbourne/Sydney. 692 pp.

Popay, I./Timmins, S. M./McCluggage, T. 2003. Aerial spraying of pampas grass in difficult conservation sites. Department of Conservation, New Zealand. Science for Conservation 218.

Staples, George W./Herbst, Derral/Imada, Clyde T. 2000. Survey of invasive or potentially invasive cultivated plants in Hawai‘i. Bishop Museum Occasional Papers No. 65. 35 pp.

Starr, Forest/Starr, Kim. 0. Forest and Kim Starr, pers. com.

Sykes, W. R./West, C. J. 1996. New records and other information on the vascular flora of the Kermadec Islands. New Zealand Journal of Botany 34:447-462.

Timmins, S. M./Mackenzie, I. W. 1995. Weeds in New Zealand protected natural areas database. Wellington, New Zealand. Department of Conservation, , Technical Series No. 8. 287 pp.

U.S. Dept. Agr., Nat. Res. Cons. Serv. 2009. The PLANTS Database. National Plant Data Center, Baton Rouge, LA 70874-4490 USA.