Gunnera manicata is one of the biggest and most spectacular architectural, herbaceous plants, commonly known as 'giant rhubarb'. It needs a lot of space and looks best grown as a specimen plant in a bog garden or at the pond edge, where the reflections from the water reveal the prickly undersides of its leaves.
A study conducted by the Royal Horticultural Society has found that Gunnera manicata has been lost to cultivation since it was introduced, and that plants thought to be Gunnera manicata are actually a hybrid of Gunnera manicata and the invasive Gunnera tinctoria, which has been named Gunnera × cryptica. Sales of all gunneras have since been banned and gardeners with existing gunneras are advised not to let them spread beyond their garden.
If you have a gunnera in your garden and would like to remove it, the best thing to do is cut it back completely and then dig it out. Alternatively, to stop it spreading simply cut flower heads in summer before they set seed, and then compost them carefully, ideally in a closed system.
For a similar effect to gunner, we recommend Rheum palmatum and Crambe cordifolia, which are not considered invasive.