Scientific name: Gunnera tinctoria (Molina) Mirbel
Common names: Chilean gunnera, Chilean rhubarb, giant rhubarb
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
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.
Native distribution area
South America (Colombia-Chile).
Distribution in Portugal
Azores archipelago (São Miguel island).
Geographic areas where there are records of Gunnera tinctoria
Europe (France, Ireland, United Kingdom), Australia, New Zealand, west USA (California).
Preferential invasion environments
Roadsides and watercourses. It also invades disturbed areas.
Impacts on ecossystems
It forms dense impenetrable thickets that inhibit the development of native vegetation.
High costs in the application of control methodologies.
In watercourses, it may obstruct the drainage channels, consequently enhancing flood risk.
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:
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
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.
Visit the webpage How to Control for additional and more detailed information about the correct application of these methodologies.
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">Invasive species">Species Ireland, 18 pp.
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.