Marram Grass, Bent or Beach Grass are common names for two species of grasses of the genus Ammophila growing almost exclusively on coastal sand dunes, where their extensive systems of creeping underground stems or rhizomes allow them to survive in very harsh and windswept ecosystems. Ammophila species are native to the coasts of the North Atlantic Ocean where they are usually the dominant species on sand dunes, but occur only rarely inland.
Marram grass is widely known as an example of a xerophyte, a plant which can withstand arid conditions such as deserts or sandy beaches. Its xerophytic adaptations (mentioned below) allow it to thrive under conditions most plants could not survive.
There are two species of marram grass, barely distinguishable from each other:
- Ammophila arenaria - European Marram Grass. Coasts of Europe (north to Iceland) and northwest Africa. Inflorescence to 25 cm long; broad.
- Ammophila breviligulata - American Marram Grass or Beach Grass. Coasts of eastern North America, including the shores of the Great Lakes. Inflorescence to 30 cm long; narrower.
The species name "Ammophila (Am-mó-phi-la) " originates from the Greek words of "Ammos", meaning Sand and "Phillia", meaning lover.
Both species are listed as invasive plants in many additional areas, where they were introduced to help reduce sand dune erosion. Particular problems are noted on the Pacific Ocean coast of North America, from California north to British Columbia.
A natural hybrid, × Ammocalamagrostis baltica, between Ammophila arenaria and Calamagrostis epigeios occurs in parts of northern Europe, mainly from the Baltic Sea west to eastern England.
In Europe, Ammophila arenaria has a coastal distribution, and is the dominant species on sand dunes where it is responsible for stabilising and building the foredune by capturing blown sand and binding it together with the warp and weft of its tough, fibrous rhizome system. Marram grass is strongly associated with two coastal plant community types in the British National Vegetation Classification. In community SD6 (Mobile dune) Ammophila is the dominant species. In the semi-fixed dunes (community SD7), where the quantity of blown sand is declining Ammophila becomes less competitive, and other species, notably Festuca rubra (Red Fescue) become prominent.
UsesNewborough women once used marram grass in the manufacture of mats, haystack covers and brushes for whitewashing.
The ability of marram grass to grow on and bind sand makes it a useful plant in the restoration of coastal defences on sandy coasts.
Marram grass has been widely used for thatch in many areas of the British isles close to the sea. The harvesting of marram grass for thatch was so widespread during the 17th century that it had the effect of destabilizing dunes, resulting in the burial of many villages, estates and farms. In 1695 the practice was banned by an Act of the Scottish Parliament:
"Considering that many lands, meadowes and pasturages lying on sea coasts have been ruined and overspread in many places in this kingdom by sand driven from adjacent sand hills .... His Majesty does strictly prohibit and discharge the pulling of bent, broom or juniper off the sand hills for hereafter".
- Ammophila arenaria on the northwest coast of North America Botanical Electronic News 183 (12 February 1998).
- ''California Conservation Corps, spearhead of Ammophila removal efforts in California.
- Jepson Manual Treatment
marram in Catalan: Ammophila
marram in Danish: Hjælme
marram in German: Strandhafer
marram in Spanish: Ammophila
marram in French: Ammophila (plante)
marram in Western Frisian: Helmgerzen
marram in Lithuanian: Smiltlendrė
marram in Portuguese: Ammophila