What coastal conditions do to plants
A seaside garden usually combines several stresses: wind, salt spray, fast-draining sandy soil and strong sun. A grass that copes with these tends to have tough, narrow or waxy leaves and a fibrous root system. Many of the same grasses that suit dry, sunny gardens also suit the coast, but salt tolerance is not guaranteed, so it is worth choosing plants with a record in your area.
If your site is dry and sunny but not salty, the wider list in drought-tolerant ornamental grasses for dry sunny gardens applies.
What kind of grass grows near the beach?
Two different groups are often mixed together:
- True dune grasses such as American beachgrass (Ammophila breviligulata) on the U.S. Atlantic and Great Lakes coasts, European marram grass (Ammophila arenaria), and sea oats (Uniola paniculata) on southern U.S. beaches. These build and hold dunes and are used for stabilizing sand rather than for decoration.
- Garden grasses that tolerate coastal conditions. These are chosen for looks and handle wind, sand and some salt.
Dune grasses are often rhizomatous and spread by underground stems, which is exactly what makes them good at holding sand and awkward in a small border. For grasses that stay put, see non-invasive clumping grasses. Some are also protected or subject to local rules, so avoid digging them from the wild.
Good ornamental grasses for coastal gardens
Salt tolerance varies with distance from the water, cultivar and how much spray reaches the plant. These are commonly suggested:
- Blue fescue (Festuca glauca), especially ‘Elijah Blue’: a compact blue clump often recommended for coastal climates, rock gardens and edging.
- Switchgrass (Panicum virgatum): a native that tolerates a wide range of conditions. The cultivar ‘Cape Breeze’ is described by growers as a compact, salt-tolerant selection.
- Giant sacaton (Sporobolus wrightii): a large, fine-textured clump grass reported to tolerate salt and drought.
- Blue lyme grass (Leymus arenarius): a blue dune grass used on sandy sites and erosion-prone edges. It spreads readily, so it suits large areas or containers better than tight borders.
- Lomandra (matt rush): a tough, evergreen, grass-like plant used widely in mild coastal regions and reported to be salt and drought tolerant.
- Flax lily (Dianella): blue-flowered, grass-like and salt tolerant, best in mild climates.
- Orange tussock or New Zealand hair sedge (Carex testacea): a bronze-orange grass-like plant popular for coastal planting in New Zealand.
- Pink muhly grass (Muhlenbergia capillaris): a warm-climate native with a fall flower haze; see how to grow pink muhly grass.
For mild-climate options from the southern hemisphere, see Australian and New Zealand grasses for mild-climate landscapes.
Where can I buy American beachgrass?
American beachgrass is commonly sold by native-plant nurseries, dune-restoration suppliers and some conservation districts, often as bare-root culms or plugs in late fall to early spring rather than year-round potted plants. Ask your state or county conservation district, coastal management office or a regional native nursery, since many run seasonal sales for dune planting.
A few cautions:
- Dune planting often needs permission, and dunes may be protected, so check local rules before planting on or near a beach.
- Do not collect plants from the wild. Some dune grasses, such as sea oats in certain states, are protected by law.
- American beachgrass spreads by rhizomes, so it is best suited to dune stabilization or large sandy areas, not a small ornamental bed.
Planting and care in sandy, windy sites
- Water while establishing. Sandy soil drains quickly, so even tough grasses need regular watering for the first season.
- Do not overfeed. Sea oats in particular are not fertilized, and most coastal grasses prefer lean soil.
- Give shelter if you can. A low fence or other plants can cut the worst wind and spray while young plants root in.
- Plant at the right depth. Plant to the depth of the previous pot and avoid burying the crown. The full method is in how to plant ornamental grasses.
- Leave winter structure, then tidy. Cut warm-season grasses back in late winter or early spring before new growth.
Grasses in a gravel or shingle garden near the coast also benefit from the techniques in grasses to grow in a gravel garden.