Gunnera tinctoria, known as giant-rhubarb or Chilean rhubarb, is a plant species native to southern Chile and neighbouring zones in Argentina. It is unrelated to rhubarb, as the two plants belong into different orders, but looks similar from a distance and has similar culinary uses. It is a large-leaved perennial plant that grows to more than two metres tall. It has been introduced to many parts of the world as an ornamental and edible plant. In some countries (for instance New Zealand and Ireland) it has spread from gardens and is becoming a weed problem. It is known under the synonyms:
Gunnera tinctoria is a giant, clump-forming herbaceous perennial. The leaves can grow up to 2.5m across. It has erect spikes of cone-shaped inflorescences (to 1m) from spring to early summer, with small flowers. The fruit is orange. The number of seeds is estimated from 80,000 per seedhead to 250,000 per plant.
In parts of New Zealand the Chilean rhubarb has become a recognised pest plant. For instance in Taranaki, on the west coast of the North Island it was spread to riverbeds, coastal cliffs and forest margins. G. tinctoria is on the National Pest Plant Accord. Under Section 52 and 53 of the Biosecurity Act, it is an offence to knowingly propagate, distribute, spread, sell, offer for sale.
In the west of Ireland, G. tinctoria is a major invasive species, in particular on Achill Island and on Corraun Peninsula, County Mayo. Its large leaves create dense shade, preventing other species from germinating or growing.
The Chilean rhubarb can be controlled by removing the entire plant. Chemical control is advised.
A similar species is Gunnera manicata (the giant rhubarb). This species may also be invasive.
- Pink, A. (2004). Gardening for the Million. Project Gutenberg Literary Archive Foundation.
- Department of Conservation (NZ) - Plant me instead. Wellington (New Zealand) 2005. ISBN 0-478-14007-X
- Department of Conservation - leaflet: "Chilean Rhubarb; shading out our natives", Wanganui. March 2006.
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