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Common Ragwort (Senecio jacobaea)

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Common ragwort

Ragwort1 is a tall plant that has lovely yellow flowers, and can often be seen growing by the side of motorways, in fields, on derelict land and occasionally in gardens. Unfortunately it is so poisonous to horses, donkeys and other livestock that it is covered by the Weeds Act 1959. More recently it has been subject to an Act of Parliament of its own, the Ragwort Control Act 2003.


Where there is no threat to livestock, ragwort is a native part of the British landscape and as such it is a beneficial plant. It supports a wide range of insects and is a major nectar source for butterflies, moths and bees, many of which are in decline in the UK.

Ragwort has dark green toothed lobed leaves, giving the plant its name, forming a rosette low to the ground. After its first winter, the rosette dies away as the main stem develops in the following year. It can grow up to a metre high, with its yellow flowers growing at the top of the stems in very flat clusters. It is part of the daisy family.

Ragwort is a biennial plant2, a rosette in the first year, and flowering for around six months (from spring to autumn) the next, and self seeds very efficiently, beginning in September during the flowering year. It can become established in an area very quickly if left unchecked. The seeds can last for over 10 years in the soil if deep enough, so disturbing soil can bring them back to the surface to begin sprouting again. It prefers to be in undisturbed, uncultivated low fertility soil, which is why ragwort is generally not found on arable land.

Every part of the plant contains pyrrolizidine alkaloids, these being the compounds that make the plant poisonous. The foliage smells very unpleasant when crushed, which helps prevent livestock from eating it.


It is not illegal to have ragwort on your land. The plant itself is not 'banned', and no attempts are being made to completely eradicate it.

Under the initial Act, if ragwort is found on any land, it is the duty of the occupant to ensure its removal if it is a threat. If it is not removed, an order may be made to the occupier to remove the plant. The amended Act simply makes it easier for prosecutions where ragwort is allowed to grow unchecked where it is a danger to animals or where it may spread to adjacent land; the act also introduces a code of practice to help with ragwort control.

If ragwort is seen, it should be reported to the landowner or occupier who should take steps to clear the land if it is a danger to livestock. If it is seen growing along the side of the road, the Highways Agency or your local authority should be contacted. If seen on railway embankments, Network Rail should be informed. However, horses and other livestock are generally not found on motorway verges or along railway lines, and so it may be that the plants can be allowed to remain. A risk assessment should be made by the proper authorities before attempts are made to wipe out the plant from these areas.


If eaten by livestock, ragwort can be fatal due to the pyrrolizidine alkaloids it contains. If eaten it has a cumulative affect and slowly destroys the liver as the toxins are absorbed from the gastro-intestinal tract. The liver's ability to repair itself is inhibited as cell damage occurs. As the liver continues to function while it is being damaged, it can be some time before the problem is discovered – usually when it is too late.

Symptoms include:

  • Weight loss and general loss of condition
  • Jaundice
  • Photosensitive dermatitis – sunburn where hair is white or sparse
  • Abnormal behaviour – depression, sleepiness or aimless wandering
  • Excessive yawning
  • Staggering gait
  • Impaired vision
  • Abdominal pain
  • Convulsions

As a living plant growing in a field, ragwort is usually ignored by livestock (it apparently tastes nasty). However, if it has been cut down and has dried, either by people not realising they should not leave cut plants in the fields, or it being undetected in a field cut for animal feed (the main cause of ragwort poisoning), it will be eaten by grazing animals as drying removes the bitter taste.

If there really is nothing else to eat, either due to over grazing, or general neglect of livestock (abandoned horses for instance, or those moved from field to field with no regard as to who owns it, or what's in it), animals will eat it, so it should be removed.

It may be poisonous to humans if it contaminates food supplies, although the risk is so low that this is mostly unlikely. Some people may have a skin reaction from the plant.


Cutting ragwort down in its early stages may allow the plant to regrow, possibly as a perennial, although doing the same in a plant's second year will work. It should be completely removed, including the roots, before it has a chance to set seed. If removing it manually it is best to wear gloves, just in case. Always remove dead plants.

Cinnabar moth caterpillars (Tyria jacobaeae) are a natural control for ragwort. They eat it because the toxins in the plant protect the caterpillars from being eaten by birds although they have other predators from the insect population. The moths are black and red, and can be seen during the day as well as at night. The caterpillars have yellow and black stripes and feed on the plants from June to August. They can strip a plant in a few days - one caterpiller takes around three minutes to eat one flower, and this helps prevent seeding.

The ragwort seed fly (Pegohylemia seneciella) and the root-feeding flea beetle (Longitarus jacobaeae) also cause damage (although only minor) to ragwort and are being considered as biological control, along with the Cinnabar moth.

Sheep have slightly more tolerance for the plant, and in some cases land owners or horse owners have attempted to use sheep to graze a field containing ragwort in an attempt to protect their horses. However, the Department for Environment, Food and Rural Affairs (Defra) advise against this: sheep can be affected by ragwort and this technique cannot be recommended on animal welfare grounds.

Fascinating Facts

Other ragwort species are not covered by the Acts, although they may also be poisonous. Fen Ragwort (Senecio paludosus) is actually protected by the law.

The other plants covered by the Weeds Act 1959 are:

  • Spear Thistle
  • Creeping or Field Thistle
  • Curled Dock
  • Broad-Leaved Dock

Ragwort also goes by the name 'stinking Billy'3 (by the Scottish), after the Battle of Culloden at which William, the Duke of Cumberland, defeated the remains of Bonnie Prince Charlie's army. William's troops are said to have spread it throughout Scotland as it was mixed in with the forage they brought. The English are said to have called it 'sweet William' after the battle for the obvious reason that they won.

1Known as 'ragweed' in some areas.2Which means that it germinates in its first year, and flowers in its second.3Or 'Willy'.

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