PLANT OF THE MONTH: Ragwort

Scientific Name: Senecio jacobaea

Habitat: bare ground or thin vegetation allows the development of seedlings.

Flowering time: July – October

Other names: Stagger weed

As July comes around, a familiar pariah plant doggedly starts to be seen flowering again in our fields and marginal spaces. 

What is ragwort?

Ragwort is a tall plant that grows to 90cm high and bears large, flat-topped clusters of yellow daisy-like flowers from July to October. Nineteen species of the Ragwort genus Senecio are found in the wild in Britain, but most of these are garden escapes or other introductions: only Senecio jacobaea is a native species to the UK. 

Why is Ragwort considered harmful? 

Ragwort is what is called a “ruderal plant”. This means it is a coloniser – it establishes easily on areas of disturbed ground.  and can thrive in areas where other wildflowers may struggle. It grows quickly and distributes many seeds that can travel a long way on the wind. In poorly managed or disturbed areas it can spread rapidly and take over. It often therefore becomes problematic in over grazed fields. 

Ragwort is classified as a “harmful weed”. This means that Natural England can require land owners to take steps to reduce or remove ragwort if it becomes “out of control”. 

This is because ragwort contains toxins called pyrrolizidine alkaloids. These, in sufficient quantities, can cause liver poisoning in horses and livestock. It is a cumulative poison that eventually leads to the rapid onset of symptoms before death. However, the symptoms are variable and resemble those of a number of other diseases.

If animals ingest ragwort, they could suffer low-level digestion of the weed for months before they start to show signs of distress. According to the charity Buglife, the lethal volume of Ragwort is around 7% of body weight for horses.

So many landowners and livestock owners react strongly to ragwort – pulling it on site, spraying it with glyphosate (which the World Health Organisation lists as a probably carcinogen) or spot burning it, as well as vociferously encouraging neighbours to do the same so as to avoid seeding other areas with the “pest”. 

But Ragwort has its uses…

So should we do the responsible thing and always pull Ragwort or run for the spray bottle if we see it growing? I would strongly argue no: please hear me out. 

Firstly, most grazing animals will avoid Ragwort growing in pasture. It tastes bad and they will only eat it if there is nothing else for them. However, it is true that ragwort in hay or silage is bad news as it is more difficult to detect and avoid. 

Ragwort is a natural part of our native flora and as such is part of the web of life in our countryside: it is needed! In a well-functioning environment, it does not spread and take over but exists in balance with other species.

Its vibrant (I would argue beautiful) yellow flowers attract many pollinators: Among the 30 species of bee, beetle, other insects and fungi supported by ragwort are the daisy carpenter bee and the cinnabar moth, meaning it has significant benefits to conservation. It is also the sole food plant for the black and red cinnabar moth.