The species is found mostly in the sublittoral region, only rarely being exposed at low tide. It occurs in more or less sheltered areas on soft mud or firm sand. Plants of sandy substrates had narrower leaves than plants growing on muddy substrates (C. H. Ostenfeld 1905). Fruits fall from the floating vegetation to the substrate and settle on the substrate ripple marks, which run more or less perpendicular to the direction of current. Seedling establishment is parallel with the ripple marks, forming vegetated ridges separated by depressions, which gradually fill with sediments, and the plants then grow laterally into them, forming a meadow (C. den Hartog 1970). The vegetation lowers the velocity of current flow, causing some suspended particles to settle out and accumulate around the base of the plants, slowly building the substrate. As more particles accumulate, the substrate gets deeper over the rhizomes, since the rhizomes grow horizontally, not vertically. Eventually, the rhizomes are too deep, and the plants begin to die back, a phenomenon followed by erosion.