Marsh grass is the primary kind of plant life in wetlands, which also are known as marshes. The grass contributes to nutrient-rich sediment being deposited by restricting the flow of water in ponds, lakes and rivers. It also helps to prevent soil erosion and supports wildlife. If you wish to create or restore a wetland on your property, then growing a kind of marsh grass suitable for your area can help. Marsh grasses are available from specialized plant nurseries.
Assess your property. If the existing shoreline or wet meadow does not already include some native marsh grasses, it might be a sign that conditions are not favorable for their growth. Suitable conditions for growing most marsh grasses include:
- At least six hours of direct sun exposure each day, which is termed "full sun."
- A gradual, graded shoreline with, if applicable, a flat area in the intertidal zone, which is the area where high and low tides meet.
- Sandy soil with minimal clay or mud deposits.
- Low wave action at the shoreline.
- Adequate room to space bare-root plants at least 12 to 18 inches apart in two to three rows.
Depending on your location and property type, you may be required to obtain one or more permits to plant marsh grass to comply with local, state and federal environmental protection regulations. Contact your location's code enforcement officer or planning board as well as your state’s environmental protection department.
If you plan to plant marsh grass on or near a property boundary line, inform your neighbors first to avoid disputes later.
Freshwater Marsh Grasses
The common cattail (Typha latifolia) is a type of grass that dominates freshwater marshes and estuaries throughout North America. It is a herbaceous perennial in U.S. Department of Agriculture plant hardiness zones 3 through 10. The semi-aquatic plant readily naturalizes in ponds and rain gardens in water up to 1 foot deep. The plant grows in organically rich, loamy soil and needs full sun or partial shade.
In addition to providing various wildlife with nesting material and protective cover from predators, common cattail's mature seed heads are used in dried flower arrangements.
Cattail colonizes via creeping “runners” underwater and can displace other native vegetation if not contained. To prevent that problem, plant cattail in tubs in ponds or other marsh settings.
Saw-grass, also called Jamaican saw-grass (Cladium jamaicense), is not a “true” grass but a sedge native to the Florida Everglades. It is also hardy in freshwater wetlands in USDA zones 8 through 11. Its common name refers to its grayish-green, saw-toothed leaves that emerge from its base. Its stems can grow 7 to 9 feet tall, depending on the depth of the water in which it grows.
Saw-grass thrives in freshwater and brackish water. Brackwish water has more salinity than freshwater but less than sea water. Although saw-grass grows best in a location that is flooded up to nine months of the year, it also can grow on dry land. In either case, it grows in any type of soil, including brackish soil, but needs some organic matter and light shade.
The saw-like teeth on saw-grass leaves can cut bare skin. So don’t try to wade through stands of this plant. Similarly, always handle plants while wearing gloves.
Common reed (Phragmites australis) is distributed throughout the world. With the exception of Alaska and Hawaii, it occurs naturally in every U.S. state and has a particular affinity for the Atlantic coastal region and the Pacific Northwest. Hardy in USDA zones 4 through 8, common reed is cultivated in ponds and other water gardens. It is a fast-growing plant that isn't particular about soil type or pH -- soil acidity -- level. It tolerates salinity associated with coastal conditions and wind. It grows, best, though when provided with a full day of direct sun exposure.
Common reed is characterized by blue-green leaves, feathery flower heads and tall stems that can reach up to 15 feet in height. What are referred to as the plant’s rhizomes are actually modified stems that are often visible because they can grow and spread above ground.
Do not try to introduce common reed to places where it does not already exist. Because each mature common reed plant typically produces 20 new plants, it can become invasive and displace other plants, including native plants.
Salt Marsh Grasses
Salt Hay Grass
Also called saltmeadow hay and saltmeadow cordgrass, salt hay grass (Spartina patens) is a hollow-stemmed plant that is hardy in USDA zones 4 through 10. As its name suggests, the plant resembles hay. Because it grows best in the high areas of salt marshes and is only an average of 2 feet tall, it is often completely under water during high tides. Aside from forming dense mats that provide a home for various kinds of wildlife and food for ducks and other birds, the presence of salt hay grass usually indicates a healthy marsh because it filters pollutants and helps to prevent erosion and flooding.
Salt hay grass is most commonly planted to restore coastal beaches, dredge fill sites and similar areas. It is also grown inland as a source of weed seed-free mulch. Spaced 6 to 12 inches apart in a full-sun site, each plant can be expected to produce up to 50 stems in just one growing season.
Smooth cordgrasss (Spartina alterniflora), also known as oyster grass and Atlantic cordgrass, is a U.S. native species distributed throughout coastal states. It is hardy in USDA zones 3 through 9 and usually planted to deter soil erosion along shorelines. It captures sediments, prevents soil from being transported away from shorelines and deflects incoming waves that contribute to bank and shoreline erosion.
Smooth cordgrass is suitable to grow in full sun or partial shade near water gardens and lakes. It tolerates any kind of soil, even heavy muck and clay. It will not, however, grow in soil that contains a lot of organic matter. It does best planted in soil below water that is 1 to 18 inches deep, but it should not be planted outside the intertidal zone.
Smooth cordgrass is a food source for grazing animals. When such animals are near, it may be necessary to cage new smooth cordgrass plants until they establish a colony.