Most horse owners are well aware of the dangers of ragwort. The toxins accumulate in the animal and ultimately cause liver failure. A small dose over a long period of time is just as deadly as one large dose. It is essential that all efforts be made to eliminate ragwort from pasture, and hay pasture in particular. Ragwort normally flowers biennially, (although it actually has the capacity to lie dormant if conditions dictate)– first year in the spring, second year in mid summer. Each plant can produce up to 150,000 seeds with a 70% germination rate. With seeds able to lay dormant in the ground for up to 20 years a minor problem can soon become a major headache. 

Control of ragwort is a laborious task. Pulling or digging of plants is best done in the spring when the plant is at rosette stage, and before flowering has completed. Gloves (not cotton) should always be worn since toxins can seep through the skin. All waste should be gathered and burned immediately since dried ragwort is more palatable to livestock, (and all efforts should be made to keep it out of hay pasture). Pulling and digging should cover the 2 year cycle of ragwort growth. Some root material is usually left when ragwort is pulled from which the plant can re-grow, but this method is cheap although very labour intensive. Chemical control takes 2 forms. Boom spraying of entire fields is effective where control of pasture has been lost. The down side to this treatment is that herbs and more delicate plants such as dandelions which provide variety in pasture are lost. Spraying can also be expensive and livestock must be removed for up to 5 weeks (10 weeks in extreme cases). Spraying must take place during active growth of plant (10 deg C +), and when leaves are dry. It must stay dry for 6 hrs after spraying to be effective.           

The second method is spot spraying with Barrier H or Roundup. This is best used at rosette stage – by the time the plant is half grown it will take 6x as much herbicide to do the job. The makers claim that Barrier H destroys the root as well, but as with all herbicide animals must be kept off pasture after treatment, in this case for 2 weeks. Barrier H can be applied any time to dry leaves and requires 24 hrs without rain to be effective.           

Good pasture management after initial control measures is the best way to stop ragwort and other broadleaf weeds. A healthy, tightly knit grass sward offers nowhere for opportunist weeds to flourish. As of yet the cheap fixes aren’t easy and the easy fixes aren’t cheap.