[Marram] is the natural inmate of a sandy soil, to which, in fact, it is peculiar. It is therefore obviously the best that could be selected for the purpose of fixing loose sands.

William Macgillivray (1830)

The strandline, highly exposed to wind and wave action, is virtually bare, mobile sand. Only hardy plants like the fleshy-leaved sea rocket and sea sandwort are able to survive. Just above the high-tide mark, where young marram grass begins to take hold, small foredunes begin to develop. With spiky, inwardly-rolled leaves, this grass has a remarkable ability to withstand dry conditions. It thrives upon wind-blown sand and even requires strong winds to break open the seed heads. Its tussocks and deep roots encourage sand to build up and help stabilise the dunes.

Behind such dunes, some up to 10 metres in height, the effects of winds and salt spray are reduced so more plants are able to grow in the bare sand among the marram. Decaying plants hold more moisture and, with less shelly sand being deposited, the soil becomes a little more acid. Marram finally gives way to red fescue and other grasses, mixed in with sand sedge, buttercups, and lady’s bedstraw, all of which can still tolerate a thin covering of wind-blown sand in winter.

On Ben Eoligarry, Barra, where the sand is blown 100 metres up the rocky slopes inland, there is an unusually abundant covering of primroses.

Sea bindweed has a curious distribution in the Hebrides. It is said to have been introduced by Bonnie Prince Charlie since it grows above the very beach in Eriskay where he stepped ashore in 1745. Somewhat inconveniently, however, it is also recorded from Vatersay, and South Ronaldsay in Orkney; places the Prince never visited!