The Nire Valley

The Nire Valley
The Heart of the Comeragh Mountains.

Friday, 6 September 2013

The out-law plant.

What is the most hated plant in Ireland? You might think of nettles and even some might volunteer broccoli, but technically, at least, you would be wrong. The title of most hated plant must go to Senecio Jacobea or Ragwort ( Buachal├ín).  What are my bases for this claim, well there is a law banning ragwort. Ask a horse owner about ragwort and be prepared for the “rant” that will follow.
Ragwort is highly poisonous especially to cattle, goats, horses and deer. Sheep seem to have some resistance to the weed but it retards there ability to thrive.  To make matters worse it is at its deadliest when it gets in among hay or silage. Normally animals will not eat ragwort as it is bitter and unpalatable, they will only eat it in areas where the land is overgrazed and the cattle are hungry. However when ragwort gets into hay, the drying process removes the bitterness but the plant looses none of its toxins, thus making it more palatable and just as deadly.

Cinnabar Moth
So are there any saving graces to this plant. Well I might volunteer one, provided I am out of ear-shot of any horse owners. Ragwort is the host plant to a colourful moth and its larvae (caterpillar) the Cinnabar Moth. Unlike many other species of moth the Cinnabar moth and its larva are both colourful and beautiful. The larva has yellow and black bands, it lives on the the ragwort and absorbs the toxins of the plant in such a way as to make it distasteful to birds that might otherwise eat it. The moth is as beautiful, with its black and red colour combinations. The moth has proven to be particularly successful as a bio-control agent for ragwort when used in conjunction with the ragwort flea beetle in the western United States. So next time you see ragwort keep an eye out for the Cinnabar moth.

Larva of the Cinnabar moth.


  1. Remember having to pull them out by the roots 'Buchallans' we called them as children....they weren't uprooted easily.

    1. I remember, you really pulled hard and suddenly they gave way, you were satisfied until you glanced around to see a field of them waiting for you. I wish those moths would hurry up and eat them.