Gunnera tinctoria (Chilean gunnera)

Gunnera tinctoria (Chilean gunnera)
Perennial herb up to 2 m, rhizomatous, with rough leaves of large dimensions and green, very small
flowers arranged in conic spikes.
Scientific name: Gunnera tinctoria (Molina) Mirbel
Common names: Chilean gunnera, Chilean rhubarb, giant rhubarb
Family: Gunneraceae
Status in Portugal: invasive species (listed in the Plano regional de erradicação e controlo de espécies de
flora invasora em áreas sensíveis)
Risk Assessment score: (in development)
Synonymy: Gunnera chilensis Lam., Gunnera scabra (Ruiz.&Pav.), Panke tinctoria Molina
Last update: 11/07/2014
How to recognise it
Perennial herb up to 2 m, with bulky rhizomes; stems with
reddish spines; lobate, rough, large leaves, and green tiny
flowers.
Leaves: alternate, dark green, with 0,8 x 1,5 m, with 5 to 7
lobes, rough and pubescent on both surfaces. Long
petioles (up to 1,5 m) covered by prickles, succulent and
edible in springtime.
Flowers: unisexual and hermaphrodite, green and very
small (up to 1 mm), sessile, apetalous and with 2 tepals,
arranged in spikes up to 1 m long, normally 3 or 4 per
plant.
Close-up of lobate leaves and long petioles
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Gunnera tinctoria (Chilean gunnera)
Fruits: reddish-orange drupes, oblong, with 1,5-2 mm diameter.
Flowering: March to June.
Characteristics that aid invasion
It propagates by seed, producing a large amount of seeds (each plant may produce between 80000 and
250000 seeds) that are easily dispersed by birds or water.
It also propagates vegetatively, by rhizome fragments, presenting very high growth rates. The rhizomes
normally grow near the ground surface, being able to reach 2 m in length.
ORIGIN AND DISTRIBUTION
Native distribution area
South America (Columbia-Chile).
Distribution in Portugal
Azores archipelago (São Miguel island).
Other places where the species is invasive
Europe (France, Ireland, United Kingdom), Australia,
New Zealand, west USA (California).
Introduction reasons
Ornamental reasons.
Preferential invasion environments
Roadsides and watercourses. It also invades disturbed areas.
ABA IMPACTS
Impacts on ecosystems
It forms dense impenetrable thickets that inhibit the development of native vegetation.
Economic impacts
High costs in the application of control methodologies.
In watercourses, it may obstruct the drainage channels, consequently enhancing flood risk.
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 Gunnera tinctoria include:
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Gunnera tinctoria (Chilean gunnera)
Physical control
Hand pulling: preferential methodology for seedlings and young plants and in small invaded areas. In
more compacted substrates, hand pulling must be made during the rainy as to facilitate the removal of
the root system. As much as possible, it should be guaranteed that there are no rhizomes and/or large
rhizome fragments left in the ground because they regenerate very vigorously, diminishing the efficacy of
this methodology.
Physical + chemical control
Cut stump method. The stems should be cut as close to the ground as possible and applied herbicide
(active substance: triclopyr, 2,4-D) to the cut surface.
Chemical control
Foliar application of herbicide: methodology applied to invaded areas of larger dimensions. Spray with
herbicide (active substance: triclopyr, 2,4-D) limiting as much as possible its application to the target
species. It should be made on the time of the plants’ greater growth.
For additional information, visit the webpage www.invasoras.pt and/or contact us at [email protected].
REFERENCES
Armstrong C, Osborne B, Kelly J, Maguire CM (2009) Giant Rhubarb (Gunnera tinctoria) Invasive Species Action Plan. Prepared
for NIEA and NPWS as part of Invasive Species Ireland, 18 pp.
CABI (2013) Gunnera tinctoria. In: Invasive Species Compendium. CAB International, Wallingford, UK. Available: www.cabi.org/
isc [Retrieved 04/01/2013].
DAISIE European Invasive Alien Species Gateway (2013) Gunnera tinctoria. Available: http://www.europe-aliens.org/
speciesFactsheet.do?speciesId=6193 [Retrieved 04/01/2013].
Global Invasive Species Database (2005) Gunnera tinctoria. Available: http://www.issg.org/database/species/ecology.asp?
si=836 [Retrieved 04/01/2013].
Penacho ML, Amaral RS, Malveiro A, Machado CAS, Aranha JTM (2009) Controlo de invasoras Hedychium gardnerianum e
Gunnera tinctoria em áreas florestais na ilha de S. Miguel - Açores. In: SPCF (ed) 6º Congresso Florestal Nacional: A floresta
num mundo globalizado, Ponta Delgada, Açores, pp. 802-806.
Penacho ML, Amaral RS, Malveiro A, Machado CAS (2011) Controlo da invasora Gunnera tinctoria em áreas florestais na ilha da
São Miguel - Açores. In: Gabriel R, Elias RB (eds) Workshop Prevenção e controlo de espécies invasoras. Universidade dos
Açores, Angra do Heroísmo, Açores, pp. 51-52.
Silva L, Corvelo R, Moura M (2008) Gunnera tinctoria (Molina) Mirbel. In: Silva L, Land EO, Luengo JLR (eds) Flora e fauna
terrestre invasora na Macaronésia. Top 100 nos Açores, Madeira e Canárias. Arena, Ponta Delgada, pp. 403-405.
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