Content on this page requires a newer version of Adobe Flash Player.

Get Adobe Flash player

 

Search in the Encyclopedia

Dieren en planten

Water en land

Mens en Milieu

Sand couch

size:

30 to 60 centimeters

color:

gray-blue

blossoms:

June through August

reproduction:

seed

life span:

perennial

distribution:

coasts of Southern and Western Europe

  • Dut: Biestarwegras
  • Lat: Elymus juncea ssp. boreoatlantica, Elymus farctus
  • Eng: Sand Couch
  • Fren: Agropyre a feuilles de jonc
  • Ger: Strandquecke, Binsenquecke
Sand couch, Johan Krol

Sand couch

Sand couch is one of the plants that makes it possible for dunes to form. This dune pioneer grows on beach plains and at the foot of dunes. Sand blown by the wind hits the plant and falls to the ground. To prevent being buried by the sand, the plant is continually growing. It forms deep roots with side roots. Just like salicorn, sand couch cannot survive without some salt in the water. As soon as a freshwater reservoir forms in the sand couch-covered dune and the plant is no longer in contact with occasional saltwater flooding, sand couch disappears and is replaced by marram grass.

  • Ideal conditions
    Sand couch, foto fitis, sytske dijksen

    Sand couch needs rain water to germinate, just like salicorn. At first, the seedling can only handle a very low percentage of salt while it builds up its tolerance. But once it is an 'adult' plant, it needs saltwater in order to strive. However there are limits. If the salt level is too high or too low, the plant will not grow well. The ideal salinity is 2%.  North Sea water contains 3% salt while rainwater contains 0%. So how does sand couch manage to live in ideal conditions?

    Once the plant starts catching sand, its root system begins to develop a network of deep roots with side branches. The side branches are located at various levels in the bottom. Each level has a different salinity, which is constantly changing due to conditions above the surface: flooding, rain, dehydration. The plant uses the roots lying at the most ideal salinity to take up water.