Mares Tail and other poisonous plants
'The toxicity to livestock, especially horses, seems to be related to the presence of the enzyme thiaminase, which combines synergistically with an undetermined selection of other chemicals in the plant to produce severe and distressing neurological symptoms, sometimes leading to death. As with Ragwort, the most likely source of poisoning is via horsetail included in hay.'
' In common with many problem weeds, Horsetail can regenerate from a single rhizome- node. It is resistant to eradication by all mechanical means, and chemical controls seem to vary widely in effectiveness even when active ingredients, timing and application methods remain the same. The resistance to chemicals is partly due to the siliceous deposits in the stem cuticles, which form a barrier to herbicide absorption, and thus reduce the amount that can be translocated through the system of rhizomes.
Another interesting characteristic of these remarkable plant is in their ability to absorb heavy metals from soil. Accumulations of Cadmium, Copper, Lead and Zinc have been found'
Other websites say the best way to get rid of it is to turf the area and mow and mow and mow until it is weakened. But it is a prehistoric survivor so it is probably the hardest thing to eradicate. Personally I wouldnt risk livestock on a heavy infestation....
Better news on Himalayan Balsam tho!
'Because Himalayan Balsam is an annual plant, it has no persistent root or rhizome system. No individual plant lives, in any case, for more than a few months. The whole future of any population, therefore, is held by the seeds, and once the seed bank is exhausted, the problem is solved. Prevention of seeding by physical means, whichever method is chosen, should be repeated for as many seasons it takes to end all germination. Under usual circumstances, eradication should be possible in three years. The size of some infestations or difficulties with access can, of course, create difficulties.
The physical means employed are grazing by animals, cutting or pulling. These last two have been dubbed "Balsam bashing".
Grazing, whether by sheep or cattle should be started about mid-April and continued throughout the growing season.'
hope this helps.....
The mares tail dies down in the winter - but presumably the roots are still there just under the surface - so does that mean it is still a problem for pigs because they will root it up?
Good new about the Himalayan Balsam though!