Smooth Cordgrass (Alterniflora)

The Smooth Cordgrass (Alterniflora) is generally described as a perennial graminoid. This is native to the U.S. (United States) has its most active growth period in the spring and summer . The greatest bloom is usually observed in the late spring, with fruit and seed production starting in the spring and continuing until summer. Leaves are not retained year to year. The Smooth Cordgrass (Alterniflora) has a moderate life span relative to most other plant species and a moderate growth rate. At maturity, the typical Smooth Cordgrass (Alterniflora) will reach up to 3.5 feet high, with a maximum height at 20 years of 0 inches.

The Smooth Cordgrass (Alterniflora) is easily found in nurseries, garden stores and other plant dealers and distributors. It can be propagated by container, seed, sprigs. It has a slow ability to spread through seed production and the seedlings have low vigor. Note that cold stratification is not required for seed germination and the plant cannot survive exposure to temperatures below -23°F. has none tolerance to drought and restricted water conditions.

Uses of : Landscaping, Medicinal, Culinary, etc.

Smooth cordgrass is the dominant emergent grass species found growing along tidal salt marshes of the Atlantic and Gulf coasts. It is utilized extensively for shoreline protection and tidal marsh restorations. Under natural conditions on tidal marshes, vigorous stands of this grass will absorb wave energy and screen suspended solids from intertidal waters, while uptaking available nutrients in the sediments. As sediments accumulate, this plant will spread away from the bank. It will tolerate petroleum contaminated soils. This cordgrass also provides food and cover to a number of marsh birds and mammals.

General Characteristics

This long-lived, warm season perennial grows to 7 feet tall, and spreads extensively by long hollow rhizomes. Soft, spongy stems up to ½ inch in diameter emerge from the rhizomes. The flat leaf blades are typically 12 to 20 inches long, tapering to a long inward-rolled tip.

In September and October seedheads which are 10 to 12 inches long emerge at the end of the stem. Each spike will hold from twelve to fifteen 2 or 3 inch long spikelets. The flowers are wind pollinated. There are approximately 175,000 seeds per pound.

Required Growing Conditions

Smooth cordgrass is commonly found growing on open coastal marshes between high and low tides from Newfoundland south to Florida and Texas. This grass can be found growing on sandy aerobic or anaerobic soils with pHs ranging from 3.7 to 7.9. Smooth cordgrass will tolerate regular inundations with 0 to 35 parts per thousand salinity.

For a current distribution map, please consult the Plant Profile page for this species on the PLANTS Website. It is not native along the U.S. west coast.

Cultivation and Care

Due to sparse and irregular seed production, smooth cordgrass is usually propagated by vegetative stem divisions. Depending on the energy effecting the planting site, either containerized (for high impact sites) or bare root (for mild impact sites) plants can be utilized. Since most marsh sites are irregular and difficult to access, hand planting is normally employed, using spades, dibbles, or planting bars. If site conditions are adequate, planting can be carried out with a mechanical, tractor drawn transplanter. Plant spacing should be between 18 and 36 inches; up to 2 feet of lateral spread can be expected annually. Smooth cordgrass grows at elevations ranging from mean high tide and above. Planting at an excessively low elevation will result in failure due to drowning and/or uprooting where wave energy is too high.In nursery rows, plants of smooth cordgrass should be spaced 12 to 24 inches apart. Under ideal nursery conditions, each planting unit will establish stands containing 25 culms per square foot. Extensive weed control is essential to producing quality nursery grown plants.

General Upkeep and Control

Stem and rhizome growth of this grass respond well to applications of well balanced commercial fertilizers. The addition of 300-500 lbs/acre of 10-10-10 fertilizer to a slow growing planting site or nursery bed is adequate to stimulate growth and development. Plants propagated under nursery conditions are easily under cut and uplifted for distribution. On field sites, debris often settles on top of established plants; this material must be removed or the plants will smother.

Pests and Potential Problems Non-threatening rust-like fungi (orange fruiting bodies on leaves) are commonly found on smooth cordgrass. Flower beetles may limit seed production. The sugar cane borer can cause the decline and death of stems.

This species is not native to the west coast of the U.S., where it becomes highly invasive.

Cultivars, Improved, and Selected Materials (and area of origin) There are 2 named varieties available on the commercial market. In 1992, ‘Bayshore’ (Maryland) smooth cordgrass was released for use on Atlantic coastal areas by the Cape May Plant Material Center, in Cape May Court House, New Jersey. In 1989 ‘Vermilion’ (Louisiana) was selected and released by the Golden Meadows Plant Materials Center in Galliano, Louisiana for use in the Gulf coastal areas. Other sources of local ecotypes are available from commercial nurseries.

Plant Basics
Growth Rate Moderate
General Type Graminoid
Growth Period Spring, Summer
Growth Duration Perennial
Lifespan Moderate
Plant Nativity Native to U.S.
Commercial Availability Routinely Available
Physical Characteristics
Bloom Period Late Spring
Displays Fall Colors No
Shape/Growth Form Bunch
Drought Tolerance None
Shade Tolerance Intolerant
Height When Mature 3.5
Vegetative Spread Rapid
Flower Color Yellow
Flower Conspicuousness No
Fruit/Seed Abundance Low
Fruit/Seed Seasonality Spring Summer
Seed Spread Rate Slow
Gardening Characteristics
Propagations (Ways to Grow) Container, Seed, Sprigs
Moisture Requirements High
Cold Stratification Required Yes
Minimum Temperature -23
Soil Depth for Roots 12
Toxic to Nearby Plants No
Toxic to Livestock No
After-Harvest Regrowth Rate Slow
After-Harvest Resprout Ability No
Responds to Coppicing No
Growth Requirements
pH Range 5.4–7 pH
Precipitation Range 40–40 inches/yr
Planting Density 2728–40000 indiv./acre
Soil Textures Coarse, Fine, Medium
Soil Depth for Roots 12
Minimum Frost-Free Days 140 day(s)
Salinity Tolerance High
CaCO3 Tolerance Low
Sustainability & Use
Leaf Retention No
Palatability Low
Fire Resistant No
Causes Livestock Bloating None

Source: USDA, NRCS, PLANTS Database,
National Plant Data Center, Baton Rouge, LA 70874-4490 USA