Marram grass and dune protection: why you must never pick the dune grass

The tough, yellow-green grass rippling over the dunes along the whole west coast may look like ordinary grass. But marram grass, to give it its name, is one of the most important things on this coast. Without it the sand would drift and the entire landscape would look different. That is why the dunes are protected, and why you must never pick the grass.

The grass that holds the sand

Marram has long, deep roots that bind the sand together, and the plant thrives on being buried by new sand: the more sand, the more it grows. In this way marram builds and holds the dunes, which are the coast's natural defence against sea and wind.

That mechanism is worth understanding. Most plants suffocate if they are buried. Marram does the opposite: when the wind lays a new layer of sand over it, it pushes up through and sends fresh roots into the layer. So the dune grows because the plant grows, and the plant grows because the dune does. It is a system that builds itself, as long as it is left undisturbed.

Without the dunes, storm surges would reach much further inland. A ten metre dune ridge is a barrier that took nature hundreds of years to build and cannot be replaced by anything you can buy.

The history of the sand drift

A few hundred years ago, drifting sand was a serious problem in West Jutland. Because the natural vegetation had been removed, partly by grazing animals in the dunes and partly by cutting heather and turf, enormous quantities of sand blew in over fields, roads and whole villages and buried them.

It was not a slow irritation, it was destructive. Farms had to be abandoned, churches silted up, and people left districts that could no longer be farmed. Eventually the state intervened and planted marram, and later dune plantations, on a large scale to bind the sand.

Much of what you see today is the result of that effort. The plantations behind the dune ridge are not original nature, they are a construction, and they are still there because the job was never finished, only stabilised.

Why the dunes are protected

The dunes are protected nature in Denmark. That means you may walk on the wide, established paths, but not pick marram, dig in the dune or make new paths through it.

Every small bit of wear counts. When the plant cover is broken the wind can get at the sand again, and a gap that starts as a shortcut becomes a channel that the wind widens. It is called a blowout, and it can take years to close again, if it ever does by itself.

So it is not just a rule. It is what holds the coast in place, and it is why you meet the signs and the built crossings everywhere from Blåvand through Henne Strand and Nymindegab to Hvide Sande and Søndervig.

How to walk here properly

• Use the built crossings when you go to the beach, even when that means two hundred metres extra.
• Stay on the paths, and do not climb the dune face, however much better the view is up there.
• Bring children in on the rule rather than forbidding. The explanation about roots holding the sand works fine on a seven-year-old.
• Keep the dog on a lead in the dune. Digging dogs make exactly the kind of hole that becomes a blowout.
• Do not pick marram for decoration. It is the one thing people do without thinking.
• Do not ride in the dune, on a bike, an ATV or anything else.

What else you see up there

Marram is the most widespread, but the dune is not only marram. Further in grow lyme grass, sand sedge and crowberry, and in the damp hollows between the dunes, the dune slacks, there is a completely different flora that is rare elsewhere in the country.

The further from the sea, the more stable the dune, and the more varied the plant life. The front, white dune is almost pure marram and sand. The grey dune behind it has moss and lichen and a thin soil. It is one of the easiest places to see an ecological gradient with the naked eye.

The coast is still moving

The West Jutland coast is not a fixed line. The sea takes sand in some places and puts it down in others, and the net movement along much of this stretch has been inland for a long time. That is why sand is pumped onto the beach in several places along the coast, including at Søndervig and south of Hvide Sande.

It is an ongoing task, not a project that finishes. The sand that is put down has to be put down again, because the sea moves it on. Marram and the dune are the cheap part of that defence, and sand nourishment is the expensive part.

That puts the rules in perspective. A path through the dune does not just cost a plant, it costs a defence the rest of us pay to maintain.

Why it concerns you as a guest

The dune is not only nature, it is also the reason the holiday home stands where it stands. The houses behind the ridge are protected by it, and on the occasions when the North Sea has taken coastline, it has been houses too close to the front that paid.

So the rules are not a formality protecting a plant. They protect a barrier that the house sits behind. That is the simplest way to put it, and it is the one that tends to stick.

And the house, when you get back from the beach

Sand in the hallway is the unavoidable part of living close to the dune. We are a local cleaning company based in Bork, and we clean holiday homes between guests in Hvide Sande, Søndervig, Henne Strand, Nymindegab, Blåvand and Bork Havn, where sand is one of the things we spend most time on. You may also want our guide to keeping the sand out of the house.