Ragwort is a very distinctive plant found commonly, growing wild, in the countryside. It is recognisable by its large, flat-topped clusters of bright yellow flowers along with its tall height and slender stem. The flowers attract a wide range of insects, mainly butterflies and moths, and has become one of their main sources of food. The most common insect seen feeding on its toothed leaves is the caterpillar of the Cinnabar Moth, therefore ragwort is seen as a vital plant for wildlife nutrition.
However, the plant contains toxic chemicals, called pyrrolizidine alkaloids, which lead to the death of horses and cattle if consumed. The animals will naturally avoid ragwort when grazing, but they cannot detect ragwort that’s present within contaminated food, so it is important to get rid of the plant altogether from areas what are grazed or from grassland that is used for the production of hay. The toxic effect that ragwort holds, builds up over time, leading to irreparable damage to the animals liver. This means that little continuous consumption is equally as deathly as consuming a large quantity at once.
The ragwort plant is most commonly seen from spring to autumn in neglected or overgrazed grasslands but also in borders or natural areas within gardens. When applying Depitox to kill the plant, the best time for treatment is late April or May. However, it is not safe for livestock to graze for at least 2 weeks after treatment as the plants can remain poisonous but as they decay the plants are attractive to animals due to their increasing sugar content, so the plants must be fully decayed before livestock is allowed to roam on the treated areas.
Ragwort is biennial, meaning that it most commonly lives for 2 years and only flowers on the second year, so it may not be recognisable until the roots are already steadily formed. However, ragwort seeds can remain in the soil for up to 15 years even if removed, so routine treatment is vital. This means that treating every autumn or every second spring is advised. As long as there is no extreme weather, treating in the autumn will control the summer seedlings from forming in advance.
The seeds are spread via the wind and a single plant is capable of producing up to 60,000 seeds. A temporary solution to this is cutting the flower head, this can reduce the seed production but is also known to stimulate the growth of side shoots which may cause a stronger growth in the following years.
The best form of treatment for ragwort is by removing and burning, or chemically treating to kill. However, if the base of the plant is damaged, the plant can live indefinitely so it is advised to treat with chemicals and not force. Digging is not ideal as the roots are likely to remain within the soil which could lead to new growth.
As we said at the start of this article, Ragwort is an important plant for many types of flying insects as well as bringing bright colour to hedgerows and gardens alike. Please think about this when considering its removal. If you don't have horses or cattle then consider leaving it alone and admire the natural beauty of the plant and the insects that will come to visit.
Depitox is a liquid weed killer that can be used to control a wide range of annual or perennial plants and has been formulated to be effective against Ragwort. It is suitable for use on amenity turf and grassland such as golf courses, verges and playing fields as well as gardens and paddocks. As with all weed killers, please read the label and full instruction before use and only use where necessary.