Sunday, 22 December 2013

Ancient Hedges and Dogs Mercury

    A sunny afternoon in Shropshire. A bit annoying that, as I was battling through torrential rain not an hour ago, when I was out on my daily constitutional.
   The walk had begun in sunshine and I was noting that though the hedges I was passing were finally devoid of leaves, the Dogs Mercury growing at the base of some of them was still very evident.
   Dogs Mercury is the plant which, back in the mid 1970s, was part of a formula for dating hedges devised by Pollard, Hooper and Moore. The number of shrub species for a thirty yard length of hedge, multiplied by one hundred, gave the age of the hedge. If this resulted in a high number and Dogs Mercury was present, it indicated a very old woodland relic hedge.
   This was fine, of course, for dating hedges in Surrey, where the formula was devised and a lot of single species hedges were planted, but during the 1980s students at Wakeman School in Shrewsbury, in association with the University of Birmingham, pointed out that hedges in Shropshire were frequently planted with multiple species and for them the formula could only be applied if a hedge had been colonised by Hazel and Field Maple as well as Dogs Mercury. Especially those parts of it which had clearly been single species planting.
   The hedges along the main road through the village, as far as I have noticed, do not have a great deal of Dogs Mercury growing at the base of them, but there are odd pockets of it growing where what might be original lengths of hedge are surviving. Along the lanes beyond the river though, there is none at all.
     The hedges with the most Dogs Mercury that I’ve found during my ramblings are those along the lanes either side of the Roman Road, and those along the Roman Road itself, which is what you would expect as they have the potential to be the oldest hedges in the village. Along all of them, though, there are lengths of original hedgerow with Dogs Mercury growing under it, and other lengths where the hedge has been replanted at some time and is no longer original.
   In the garden, or perhaps looking over your hedge at it, because its presence isn’t really encouraged in modern gardens, growing along the base of a hedge near to the site of an old abandoned dwelling maybe, where some cottager used it for flavouring beer in the days before the introduction of hops, look out for the mildly aromatic, indented, mid-green leaves with silver undersides, of Artemisia vulgaris, Mugwort, also known as St John’s Plant, because a crown of its sprays was worn as a protection against evil forces on St John’s Eve.

                                                    

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