Ragwort is extraordinarily successful; all the “injurious weeds” named in the 1959 Weed Act are.
When allowed to flower and set seed, ragwort is biennial. As a biennial, its life cycle is spread over two years; it flowers in its second year and after setting its seed the plant usually dies. These are general rules; ragwort is very adaptable and can flower in its first year as it did in response to last year’s drought or can just refuse stubbornly to die at the end of its second year. There are studies that show up to 70% of ragwort plants will persist after they have flowered.
Complying with the 1959 and 2003 Acts
It is a survival specialist and has two distinct methods of reproduction, both with a clever twist. Firstly, a plant can produce as many as an astonishing 150,000 seeds in a year; each is provided with a parachute for wind distribution but some also have hairs that will enable them to latch onto animal fur or birds’ feathers.
The seeds come in variable weights depending on where on the flower-head they develop; the lightest will blow away many metres but the heaviest, produced at the end of the season, will fall straight down into the space that will be left when the parent plant dies. The twist: seeds can wait in the soil for twenty years before they germinate; your field, ragwort-free for a decade, will suddenly be full of poisonous yellow flowers buzzing with invertebrates.
Secondly, ragwort can reproduce vegetatively; any attempt at digging up or pulling out during its growing season will result in every last little piece of root left behind making a new plant. The twist here is that if you cut it down to prevent the flowers making seed, it can become a perennial, vegetatively producing new clones at the outer edges of its root system until it is allowed to flower and seed. It wins coming and going.
We understand its ecological importance
We understand its ecological importance as a late season source of nectar and pollen. We know that there is much discussion, online and off, about its conservation value, the level of its toxicity and whether or not it should be subject to legislation. As it stands, Wiltshire Council is obliged, as the landowner, to comply with the 1959 and 2003 Acts which require that the spread of ragwort be controlled.

Conservation status: Common
Is this poisonous to dogs/ horses etc
Yes, it is poisonous; it tastes nasty so animals don’t usually eat it. Dried, in hay, it loses its bitterness and then it gets eaten. The park is farmed by a tenant farmer who takes a crop (or two) of hay from it and so we keep the ragwort in check. August is ragwort pulling time; very hard work.