Benweed is the common name for this pernicious weed. It is also known as ragwort (Senecio jacobaea). It spreads vigorously and is very difficult to eradicate if allowed to seed. It is so poisonous that it is illegal in Ireland to allow it to grow on your property. In certain nature reserves in mainland Britain, where ragwort is defined as "a listed injurious weed", one of just five, and where landowners must demonstrate that they have done their best to manage it, paradoxically it is not discouraged in some nature reserves as it is the host of a number of important moths and butterflies.
Horses and cattle are particularly susceptible to ragwort poisoning although they generally avoid its bitter taste. In contaminated silage or hay the cattle cannot distinguish the ragwort and this is where the greatest threat of poisoning lies. There is no antidote for poisoning of animals by ragwort.
was one of the offences for which the Royal Irish Constabulary (RIC)
were almost guaranteed to prosecute. This role was taken over by the
Garda Síochána in the Republic of Ireland and by the Royal
Ulster Constabulary in Northern Ireland. Now the role has passed to
the respective government's departments with responsibility for Agriculture
and ragwort now seems to be a growing problem, both north and south
of the border.