In Ireland, hedges were planted to enclose “town lands” from the medieval period onwards. Known as townland boundaries, these are some of the most ancient and species-rich Irish hedges.
A recent survey of hedgerows in County Monaghan found that 12% of the hedges formed part of a townland boundary. More importantly it showed that where townland boundary hedges linked into native woodland they were much more likely to have a rich variety of species, including plant species less common in other hedges such as wood sorrel, ground ivy and hedge woundwort.
There’s a useful website about Irish hedges, with a good selection of links, here: