Have you got giant rhubarb in your garden? A European-wide ban on the sale of this invasive non-native plant comes into force today. If you already have the plant, also known as Gunnera tinctoria, in your garden you can keep it, but you must act responsibly, as allowing Gunnera tinctoria to grow or spread outside your garden could be an offence.
We asked our Invasive non-native species adviser, Stan Whitaker, how should people manage the plant in their gardens? Stan said: “We are encouraging people with Gunnera in their gardens to consider either removing the plant entirely, or alternatively cutting off the flower heads each summer before they set seed, then composting with care.
“Seeds are typically formed by June, and ripen between July and October. We recommend cutting the flower spikes close to their base, with a gardening knife or pruning saw, in July or August.”
Allowing a non-native plant to spread into the wild is an offence under the Wildlife and Countryside Act 1981. However, Stan said: “Gardeners don’t need to worry about getting a criminal record or having a control order placed on their land, provided they take reasonable steps to prevent invasive plants, like Gunnera, escaping into the wild.”
If Gunnera tinctoria is left to spread in the wild we’re likely to see an increasing area of land lost to grazing as well as significant impacts on our biodiversity and road-side drains. You can help us to keep Scotland Gunnera tinctoria-free by reporting any sightings of the plant in the wild to Scotland’s Environemt Web.
We are working on an ambitious project to wipe out giant rhubarb in in the Western Isles and want to stop its spread on the west coast of Scotland and beyond. Originally from South America, the distinctive large leaved plant was introduced as a garden ornamental but has spread rapidly over crofts and ditches and is becoming increasingly problematic for both crofters and wildlife in the Outer Hebrides.
Some of the plants growing in gardens will be the Brazilian or Chilean rhubarb, Gunnera maticata, which is not invasive. It’s easy to tell the mature plants apart: Gunnera manticata has reddish bristles and spines on the stem, whereas the invasive Gunnera tinctoria has pale bristles with weak spines.