American beachgrass grows naturally on dunes that border beaches along the Atlantic and Gulf of Mexico coastlines, but does not fare well in the richer, darker, and less oxygenated soils of the inland marshes and the bay sides of barrier islands. Beachgrass stands up well against the continuous salt spray of the crashing waves and ocean breeze and the blazing heat of the summer sun on the dune sands.

View a low magnification image of American beachgrass (thin section).

Most importantly for beach lovers and coastal dwellers, the roots and horizontal runners or rhizomes of beachgrass are extensive and massive. In addition to diving below the sand, seeking fresh water for life support, the root mass stabilizes the dunes. Climbing or driving on vegetated dunes can kill the beachgrass and destabilize the dunes, leading to sandstorms and dune blowouts. In severe cases, particularly during hurricanes and strong coastal storms with destructive onshore winds and waves, massive beach erosion and significant island and mainland coastal economic damage may occur if beachgrass stands are removed or damaged.

Well adapted to coastal dune life, on the hottest days, the beachgrass leaves curl inward to reduce the area exposed to direct and reflected solar light and radiant heat. In this manner, beachgrasses conserve vital freshwater resources. Beach restoration projects that are most successful in terms of longevity, cost-effectiveness, and side benefits to associated wildlife incorporate beachgrass plantings with dune stabilization and restrictions to human disturbances. Although attractive to affluent summer residents and vacationers, barrier island and other forms of coastal development in the United States have often destroyed the tiny and often overlooked beachgrass plants. This oversight has resulted in storm, flood, and erosion damage to houses and public infrastructure totaling in the billions of dollars, and has inflated coastal homeowner insurance costs.