The ‘Galloway hedge’ or ‘sunk fence’, is a combination dry stone wall and thorn hedge, rather similar to the Irish ditch with quicks and found primarily in South West Scotland.
This design is especially suited to fencing along the contours of hill and valley sides, in situations where the climate is acceptable for hedgerow shrubs, but where walling stone is available as well. A wall alone would have to be very high to keep sheep from gaining access from the uphill side, and a hedge alone would likely become gappy unless frequently laid.
According to Rainsford-Hannay (1972), the Galloway hedge was invented by Hamilton of Baldoon in 1730, and copied extensively by Lord Selkirk of St. Mary’s Isle. He describes its construction. First, make a horizontal cut along the slope to form a level platform, and throw the spoil uphill. Then place the foundation stones and erect a double dyke with the uphill side vertical and the other side given a good batter. There should be a scarcement of at least 4″ (100mm) on the downhill side, but little or none on the other. When the dyke is raised to the top of the undisturbed soil, lay long thorn plants horizontally across the dyke with their roots in the soil. Finish building the dyke around the plants to a height of 4’6″ (1.3m) including the locked top.
For the first couple of years, stock should be kept off the fields to both sides of the new Galloway hedge, to allow the thorns to grow. After three years the plants should be big enough to defeat sheep and cattle. Although the combination of stone and thorn makes a good barrier, it does require trimming and general maintenance each year, which may be why few are now being built.
The above type appears to be rare in Galloway nowadays, although there are numerous roadside hedges growing out of low retaining walls, where the field height is perhaps 2-3′ (600-900mm) above road or track height.
Whilst the general argument is that shrubs and trees destabilise walls, the case is not that clear when looked at in relation to the Galloway hedge. As long as the wall has been well built the growing hedge seems to tighten the stone work. Semi-derelict Galloway hedges seem particularly tight around the shrubs where the stones have been forced together. It is the parts of the walls between the shrubs which have frequently collapsed, although this may be due to the squeezing effect of the shrubs. During construction, space was probably left around the stem to allow for growth.
