Cortaderia selloana (pampas grass)

Cortaderia selloana (pampas grass)
Robust, perennial grass, up to 2,5 m, rhizomatous, with large whitish-silver plumes.
Scientific name: Cortaderia selloana (Schult. & Schult.f.) Asch. & Graebn.
Common names: pampas grass, silver pampas grass
Family: Poaceae (Gramineae)
Status in Portugal: invasive species
Risk Assessment score: (in development)
Synonymy: Arundo selloana Schult, Cortaderia dioica (Spreng.) Speg, Cortaderia argentea (Nees) Stapf,
Arundo selloana Schult. & Schult., Gynerium argenteum Nees
Last update: 09/07/2014
How to recognise it
Perennial grass up to 2,5m, rhizomatous, with a large
rosette with basal leaves that may reach 3,5 diameter,
with numerous culms that are around the same size as
the rosette in the female flowers, and 2 times larger
than in the male flowers.
Leaves: greyish or bluish-green, linear with razor sharp
margins and an acuminate apex forming a “v” when
seen with a transversal cut.
Flowers: arranged in panicles, similar to large plumes,
dense, whitish-silver (sometimes light violet), with 4070 cm, being able to reach over 4 m high.
Fruits: dark caryopses of 2-2,5 mm length.
Flowering: August to October.
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Close-up of a young basal rosette after cutting
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Cortaderia selloana (pampas grass)
Similar species
Cortaderia jubata (Lemoine ex Carrière) Stapf is similar, but the panicle is looser and shows a more
pinkish or dark violet colour; the culms are 2-2,5 times longer than the leaves’ rosette; the leaves are
bright green to dark green.
Characteristics that aid invasion
It propagates by seed producing many seeds (a female plant may produce up to one million seeds), which
are dispersed very efficiently by the wind, originating invasion foci in distant locations.
ORIGIN AND DISTRIBUTION
Native distribution area
Tropical part of South America (Chile and Argentina).
Distribution in Portugal
Mainland Portugal (Minho, Douro Litoral, Beira
Litoral, Estremadura, Alto Alentejo, Baixo Alentejo,
Algarve).
Other places where the species is invasive
Europe (Spain, Italy, United Kingdom), western USA
(California), Australia, New Zealand.
Introduction reasons
For ornamental reasons.
Preferential invasion environments
Coastal dunes, along roadsides and disturbed areas (wastelands and abandoned areas). It is an
opportunistic species that establishes itself in areas where the native vegetation was eliminated or
disturbed.
It adapts to a large variety of soils but it grows better in deep soils, with good drainage. It is frequently
found in areas with a lot of sunlight that receive some humidity. It is sensitive to ice in the seedling stage,
becoming more tolerant in maturation.
IMPACTS
Impacts on ecosystems
It grows vigorously forming some dense stands that dominate grasslands and shrublands; it creates
barriers to fauna circulation and uses available resources for other species.
Its razor sharp leaves may inhibit human circulation in invaded areas.
Economic impacts
Its control methodologies are quite expensive.
Other impacts
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Cortaderia selloana (pampas grass)
Allergies.
The razor sharp leaves may injure people.
Natura 2000 network habitats more subject to impacts

Fixed coastal dunes with herbaceous vegetation («grey dunes») (2130);

Dunes with Salix repens ssp. argentea (Salicion arenariae) (2170);

Wooded dunes of the Atlantic, Continental and Boreal region (2180);

Humid dune slacks (2190);

Malcolmietalia dune grasslands (2230);

Wooded dunes with Pinus pinea and/or Pinus pinaster (2270);

Inland dunes with open Corynephorus and Agrostis grasslands (2330).
CONTROL
Controlling an invasive species demands a well-planned management, which includes the determination
of the invaded area, identifying the causes of invasion, assessing the impacts, defining the intervention
priorities, selecting the adequate control methodologies and their application. Afterwards it is
fundamental to monitor the efficiency of the methodologies and recuperation of the intervened area as
to perform, whenever necessary, the follow-up control.
The control methodologies used for Cortaderia selloana include:
Physical control
Hand pulling: preferential methodology for seedlings and young plants present in sandy soils. In more
compacted substrates, hand pulling must be done in the rainy season as to facilitate the removal of the
root system. It should be guaranteed that no large roots and/or rhizomes remain in the ground, once
they recuperate easily. Hand pulling should be done with individual protection equipment once the
leaves are very sharp.
Mechanical pulling: it is applied to larger plants. It should be guaranteed that no large roots and/or
rhizomes remain in the ground, once they recuperate easily.
Cutting and removing the rhizomes: it is applied to larger plants each time hand pulling is not an option.
The cutting may be done with a chainsaw or brushcutter. The removal of the root parts may be done by
using manual and/or mechanical equipment. The cutting should be done with individual protection
equipment, because that the leaves are very sharp.
Panicle cutting. It should be done before the seed dispersion. One should guarantee that no panicle is left
uncut. The cut panicles should be removed from the location and put in double bags to be posteriorly
destroyed or the await degradation.
Physical + chemical control
Cut stump method. The stems should be cut as close to the ground as possible and applied herbicide
(active substance: glyphosate) on the new sprouts.
Controlo químico
Foliar application of herbicide: Spray with herbicide (active substance: glyphosate) limiting as much as
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Cortaderia selloana (pampas grass)
possible its application to the target species.
For additional information, visit the webpage www.invasoras.pt and/or contact us at [email protected].
REFERENCES
CABI (2012) Cortaderia selloana. In: Invasive Species Compendium. CAB International, Wallingford, UK. Available:
www.cabi.org/isc [Retrieved 10/11/2012].
Global Invasive Species Database (2012) Cortaderia selloana. Available: http://www.issg.org/database/species/ecology.asp?
si=373&fr=1&sts=sss [Retrieved 10/11/2012].
Marchante E, Freitas H, Marchante H (2008) Guia prático para a identificação de plantas invasoras de Portugal Continental.
Imprensa da Universidade de Coimbra, Coimbra, 183pp.
Herrera M, Campos JA (2006) El carrizo de la pampa (Cortaderia selloana) en Bizkaia. Guia practica para su control. Diputacion
Foral de Bizkaia, Bilbau, Spain, 43 pp.
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