Ragwort is a common flowering plant, native to Europe but categorised as a ‘weed’ species. It’s a tall plant that can grow up to 90cm in height between July and October. It’s usually biennial, which means that it lives for two years and flowers in its second year. If the base of the plant is damaged then it behaves like a perennial (it may live for three years or longer).
Ragwort is perfectly adapted to dispersing its seeds in response to herbivore activity. It produces a large number of seeds that are dispersed by the wind, especially when it’s disturbed by animals, people, vehicles or elements such as high winds. This maximises its spread over relatively large areas.
Where does ragwort grow?
Ragwort is often found on brownfield sites, pastures and road verges but can occur in a range of different areas. It’s a pioneering opportunistic species, which means it commonly establishes on ground that’s been disturbed.
Why is ragwort important?
The species is an important source of nectar and pollen. It’s a food plant for many insect species, including the cinnabar moth. However, ragwort is deemed to be toxic to livestock when taken in high doses.
Animals will naturally avoid ragwort when grazing unless pasture is overgrazed and there’s a lack of food, but they can’t detect ragwort that’s present in hay. A large amount of ragwort — estimated to be around 5 – 25% of total body weight for horses and cattle — has to be ingested for it to be poisonous.
Ragwort is listed as a weed in the Weeds Act 1959. This means that where large numbers of a weed species are growing on land, the landowner can be served with a notice requiring them to act to stop the spread of that species.
The Ragwort Control Act was introduced in 2003. This act aims to clarify and provide more detail on ragwort control in relation to the Weeds Act 1959. It states that ragwort doesn’t need to be eradicated entirely, but that strategic control is recommended where ragwort levels threaten the health and welfare of grazing animals and their forage.
“Patience may be needed to allow natural succession to replace ragwort”
Ragwort control may require the use of herbicides, which can be damaging to the environment. Cutting and removing the plants can be labour intensive and expensive but is kinder to the land. In rewilding projects, patience may be needed to allow natural succession where different species grow over time to replace the ragwort.
Examples from the field
The Knepp Estate
The Knepp Estate mows 50 metres around its boundary to control ragwort and minimise the spread to adjacent landholdings. They work with their neighbours to share their rewilding vision, taking onboard any concerns and taking action where needed.
Ragwort levels have fluctuated on site, and were particularly high in the first few years of rewilding when previously ploughed land was left to recover. Levels have reduced as natural succession occurs. In many places ragwort is naturally outcompeted by other species.
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Wicken Fen National Nature Reserve
Wicken Fen has tried a variety of methods of establishing ground cover to minimise the spread of ragwort including natural regeneration, seeding and hay spreading. Results have been mixed with no single measure preventing ragwort seed drifting on to neighbouring land.
The project now manages their ragwort through a zoning plan. Where boundaries that adjoin neighbouring land with livestock/hay production (high risk), a 50 – 60 metre margin is treated chemically with a suitable herbicide. This is not ideal, as it affects biodiversity within the zone.
There seems to still be a fluctuation in coverage, which potentially could be linked to the impact of treatment. Treatment often results in a few years of low ragwort production, but after a few years they return (either from existing seed source or blown in from adjacent areas).
Plants are only topped as a last resort, for example if the treatment is delayed by poor weather, and then arisings are removed.
Away from these areas, vegetation is left. These areas support fluctuating levels of ‘weed’ species (ragwort and thistle) over the 20 years of rewilding. In many areas, these plants are being replaced by other flowing species, but in others early colonisers are still present.