Life on a wind-blown beach plain is not easy, but sea rocket is a hardy plant that is resistant to such rough circumstances. It grows relatively far from the high tide line on top of buried flood marks or other organic material, just like sand couch. Without these nutrients, particualrly nitrogen, sea rocket cannot grow. Both sea rocket and sand couch are important plants for dune formation. Onces they take root, they catch sand which slowly turns into a dune.