A wall that has been standing for a long time is full of life. On the hill wall, the north-facing side, which sees little sun, is covered in moss, thick and soft, in several shades of green. The south-facing side is drier, and its stones are patched with lichens: pale gray rosettes, crusts of yellow and orange, small leafy ones that curl at the edges. Lichens grow very slowly, some only a fraction of an inch in a year, so the larger patches on the old stones are very old indeed.
In the joints between the stones, where a little soil has gathered, small plants take root. There are tiny ferns along the shady side, with fronds no longer than a finger. There are low cushions of a plant with small round leaves and, in late spring, small pink flowers. There is grass, of course, along the foot of the wall, longer than the grass in the field because nothing grazes it there. In the cracks, there are snails, beetles and spiders. Wrens nest in the wall in spring, slipping in and out through holes that look far too small for them.
None of this does the wall any harm. The plants that grow in a dry-stone wall are mostly small and shallow-rooted, and the moss and lichens only cover the surface. Wallers sometimes say that a wall is only properly settled once the moss has come back to it. They mean that it takes a few years for the stones to bed down into their final positions, and that by the time the moss has grown over the joints, the wall has finished moving and will stay as it is.
Walking up the path on a still day, it is possible to go a long way beside the wall without thinking about it at all. It is just there, on the left going up and on the right coming down, about the height of your shoulder, gray and green, with the throughs sticking out a little at waist height and the copes along the top. Now and then a wren flicks out of it. Now and then you put a hand on it, without thinking, at a steep part of the path.
The mended stretch from last spring is about two thirds of the way up, just past the spring. It is still a little paler than the rest, though less so than it was. The moss has started along its lower courses, on the shady side. In another year or two it will be hard to find.
The wall will need mending again at some point, probably somewhere near the spring, where the ground is wettest. When that happens, the same work will be done in the same order. The gap will be taken down to sound wall, and the stones laid out on the grass, and the footings checked, and the faces built up course by course with the hearting packed between them, the throughs across at half height, and the cover band and copes on top. It will take a few days. Then the frames will come out of the ground, and the wall will go on standing, as it has for a long time, beside the path up the hill.