Ragwort

Ragwort (Senecio jacobaea) is not usually a significant problem in gardens, but its poisonous qualities can make it a serious weed of paddocks and gardens backing onto fields grazed by horses or cattle.

Common ragwort. Image: RHS

Quick facts

Common name Common ragwort
Latin name Senecio jacobaea
Areas affected Waysides, grazing land and uncultivated ground
Main causes Weed poisonous to cattle and horses
Timing Seen from spring to autumn; treat in late spring or autumn

What is ragwort?

Ragworts (Senecio spp.) are poisonous weeds of which Senecio jacobaea is the most common. It can become a major weed of waste or other uncultivated ground.

Appearance

Ragwort is a tall erect plant to 90cm (3ft) bearing large flat-topped clusters of yellow daisy-like flowers from July to October. It has finely divided leaves with a basal rosette of deeply-cut, toothed leaves.

The plant is usually a biennial (living only two years and flowering in its second year) but damage to the base of the plant can make the plant behave like a perennial (living indefinitely), as new rosettes are formed.

The problem

Ragwort is rarely a problem in gardens but may occur in pony paddocks, railway embankments and areas of unimproved pasture. Cattle and horses are particularly susceptible to poisoning. Cutting, wilting and the treatment with herbicides make ragwort less unpalatable to livestock and poisoning mainly arises from eating contaminated hay.

Common ragwort produces large numbers of seeds which are dispersed by the wind.

The Weeds Act 1959 specifies five injurious weeds: common ragwort, spear thistle, creeping or field thistle, broad-leaved dock and curled dock. It requires landowners to 'take such action as may be necessary to prevent the weeds from spreading'. Although this does not mean it is illegal to have ragwort (Senecio jacobaea) growing on their land, landowners would be advised to control it where it poses a risk of spreading onto other properties, especially onto land grazed by horses and cattle.

The Code of Practice appended to the Ragwort Control Act 2003 is still available and gives more guidance to land managers on how to prevent the spread of ragwort.

Control

Non-chemical controls

Non-chemical options are limited. Cutting at the early flower stage reduces seed production but can stimulate the growth of sideshoots, resulting in more vigorous growth in the following year. Cut plants are a serious risk to grazing animals and may still set seed. They should be removed and burnt.

Pulling is practical where weed numbers are low, but the benefit is only temporary. Roots remaining in the soil will give rise to new plants.

Chemical controls

Glyphosate

Glyphosate (e.g. Scotts Roundup Ultra, Bayer Garden Rootkill weedkiller, Bayer Garden Super Strength Weedkiller, Doff  Maxi Strength Glyphosate Weedkiller or Westland Resolva Xtra Tough Concentrate; or for spot treatment use Scotts Roundup Gel) can be used to clear small infestations but apply carefully as it will kill any green plants it comes into contact with.

Lawn and grassland weedkillers

In more heavily infested grassed areas, MCPA and 2,4-D (e.g Vitax LawnClear 2, Westland Resolva Lawn Weedkiller Concentrate or Doff Lawn Spot Weeder) are selective weedkillers that are effective against ragwort when applied at the higher rates mentioned on the product label. These weedkillers also affect other broad-leaved plants such as clover.

To control mature plants in pastures apply weedkillers in late April or May. Grazing is not safe for at least four to six weeks after spraying as treated plants remain poisonous. Allow plenty of time for the weeds to decay. Established plants are less susceptible to spraying, particularly after the stem elongates in early June. Spraying from September to November during mild and settled weather will control summer seedlings.

Spraying has to be a routine procedure every autumn, or every second spring, as ragwort seeds remain viable in the soil for up to 15 years. Weedkillers temporarily increase the attractiveness of ragwort to grazing stock, so to be sure of preventing poisoning, keep animals off sprayed pastures until the weed has disintegrated and disappeared.

Weedkillers suitable for large-scale pasture use are available only to qualified professionals. Contact agricultural contractors to treat paddocks and similar areas (see Yellow Pages or the National Association of Agricultural Contractors). For garden use only, consider using triclpyr (Vitax SBK Brushwood Killer) in rough grassed areas and lawn weedkillers for lawns.

Inclusion of a weedkiller product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener.

Download

Weedkillers for gardeners (Adobe Acrobat pdf document outlining weedkillers available to gardeners; see sections 1a and b, and 4)

Links

Chemicals: using a sprayer
Chemicals: using safely and effectively
Chemicals: using spot and broad-scale weedkillers
Weeds: non-chemical control

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  • Bill Ellson

    By Bill Ellson on 30/07/2014

    The vast majority of seeds fall within a couple of metres of the plant. The 'urban myth' of seeds distributed by the wind seems to have arisen from people thinking that because they pulled all the plants one year that the plants the next year must have blown in. The truth of the matter being that pulling ragwort invariably results in leaving root fragments that regenerate. There is no general duty on anybody to control ragwort. The Weeds Act 1959 merely gives the Secretary of State power to serve a notice requiring a landowner to control ragwort. Both Acts can be found at www.legislation.gov.uk . Neither horses nor cattle will eat the living plant because of its extreme bitterness, unless they have been starved. The real problem arises when ragwort gets into hay or other feed as when dry it loses its bitterness. It is a criminal offence to sell hay contaminated with ragwort. Ragwort is a native species that hosts a goodly number of insects, particularly the distinctive orange and black striped Cinnabar Moth caterpillar.


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  • Sue Bebbington

    By Sue Bebbington on 30/07/2014

    The comment from Bill that ragwort only seeds short distances is I believe from tests carried out some time ago when even those conducting the tests accepted that the plants monitored were not subjected to high winds. Ragwort growing on, for example, road verges is subject to turbulence which results in a far wider spread than Bill would suggest. There is a move by some conservation groups to repeal the Weeds Act and Ragwort Control Act, these acts only require control of ragwort where it is likely to spread to grazing land and land used to produce preserved forage eg hay/silage which Bill accepts is a real problem. Ragwort is common, prolific and very adaptable, it can be seen growing widely and is very difficult to control once established. Pulling is only one method of control, done correctly and at the right time it is reasonably effective and avoids the use of herbicides. More information on ragwort, the legal aspects and responsibilities of all landowners, large or small, can be found at https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/69264/pb9840-cop-ragwort.pdf


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  • Sue Bebbington

    By Sue Bebbington on 30/07/2014

    The comment from Bill that ragwort only seeds short distances is I believe from tests carried out some time ago when even those conducting the tests accepted that the plants monitored were not subjected to high winds. Ragwort growing on, for example, road verges is subject to turbulence which results in a far wider spread than Bill would suggest. There is a move by some conservation groups to repeal the Weeds Act and Ragwort Control Act, these acts only require control of ragwort where it is likely to spread to grazing land and land used to produce preserved forage eg hay/silage which Bill accepts is a real problem. Ragwort is common, prolific and very adaptable, it can be seen growing widely and is very difficult to control once established. Pulling is only one method of control, done correctly and at the right time it is reasonably effective and avoids the use of herbicides. More information on ragwort, the legal aspects and responsibilities of all landowners, large or small, can be found at https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/69264/pb9840-cop-ragwort.pdf


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  • Sue Bebbington

    By Sue Bebbington on 30/07/2014

    The comment from Bill that ragwort only seeds short distances is I believe from tests carried out some time ago when even those conducting the tests accepted that the plants monitored were not subjected to high winds. Ragwort growing on, for example, road verges is subject to turbulence which results in a far wider spread than Bill would suggest. There is a move by some conservation groups to repeal the Weeds Act and Ragwort Control Act, these acts only require control of ragwort where it is likely to spread to grazing land and land used to produce preserved forage eg hay/silage which Bill accepts is a real problem. Ragwort is common, prolific and very adaptable, it can be seen growing widely and is very difficult to control once established. Pulling is only one method of control, done correctly and at the right time it is reasonably effective and avoids the use of herbicides. More information on ragwort, the legal aspects and responsibilities of all landowners, large or small, can be found at https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/69264/pb9840-cop-ragwort.pdf


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