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| ## smooth cordgrass {#smooth-cordgrass .Title-Header}                 |
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| *Spartina alterniflora* Lois.                                         |
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| Plant Symbol = SPAL                                                   |
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## *Contributed By: USDA NRCS Louisiana State Office*

# Alternative Names![](media/image2.jpeg){width="1.0909722222222222in" height="5.540972222222222in"}

saltmarsh cordgrass, oystergrass, saltwater cordgrass

# Uses

*SE US Coastal & Shoreline Restoration*: Smooth cordgrass is a unique
plant species that when established properly and under applicable
conditions has proven to provide significant erosion protection to
shorelines, canal banks, and other areas of coastal wetland loss.

Smooth cordgrass is used primarily for erosion control along shorelines,
canal banks, levees, and other areas of soil-water interface. In
addition, smooth cordgrass is an effective soil stabilizer used on
interior tidal mudflats, dredge-fill sites, and other areas of loose and
unconsolidated soils associated with marsh restoration. When established
in conjunction with shorelines, smooth cordgrass provides an effective
buffer that dissipates energy, reduces shoreline scouring, and traps
suspended sediments and other solids. Dense stands of smooth cordgrass
are efficient users of available nutrients, producing significant
amounts of organic matter. The cumulative effects of organic matter
production, sediment trapping, and erosion control not only provide
shoreline protection but also accelerate sediment accumulation and
near-shore building. Consequently, smooth cordgrass is a sustainable and
renewable restoration resource, and when properly established and in the
appropriate habitat, will persist and potentially remain effective
indefinitely.

# Status

Smooth cordgrass is a native species critical to Barrier Island and
wetland restoration along the southeastern coastal states, while it is
introduced into areas on the Pacific coast, where has become an
aggressive invasive species. Please consult the PLANTS Web site and your
State Department of Natural Resources for this plant's current status,
such as, state noxious status, and wetland indicator values.

**Weediness**

Smooth cordgrass has been introduced along the U.S. West Coast and is
very invasive. Consult the links found at the bottom of the PLANTS Plant
Profile for additional information regarding this species along the
Pacific coast, particularly in California and Washington.

# Description

*General*: Smooth cordgrass is a herbaceous, native, warm season grass
that forms dense vegetative colonies along shorelines and inter-tidal
flats in coastal wetlands. Smooth cordgrass is a robust, rapidly
spreading plant, tolerant to fluctuating water depths and salinity.
Smooth cordgrass spreads primarily by vegetative propagation, producing
new stems from an extensive system of underground rhizomes. Plant height
will vary according to site conditions, but generally will range from
24" to 72." Colonies tend to grow parallel to and continuous along
shorelines; the width and thickness of a vegetative colony is controlled
by a number of site-specific conditions such as elevation,
shoreline-slope, and frequency, depth, and duration of flooding.

*Distribution*: Generally, this species occurs in the coastal states
along the U.S. It is not native on the West Coast. For current
distribution, please consult the Plant Profile page for this species on
the PLANTS Web site.

# Establishment

*Adaptation*: Smooth cordgrass is an inter-tidal brackish plant species.
It is described as a facultative halophyte; that is, it will tolerate
salt, but salt is not a requirement for its growth. Smooth cordgrass can
be established in freshwater, however, numerous field trials have
demonstrated that smooth cordgrass is difficult to establish and will
not persist under freshwater field conditions. The ideal salinity range
for establishing and growing smooth cordgrass is 8 to 33 parts per
thousand or brackish to saline habitats. Smooth cordgrass can be
established and will persists in areas of elevated salinity (such as
salt-flats and tidal lagoons), however plants in high saline habitats
tend to be stubby and less robust, generally resulting in thinner and
more open vegetative stands.

Of primary importance in site selection is that the site be inter-tidal.
Smooth cordgrass is critically sensitive to reduced soil sulfides, a
condition common to anaerobic and brackish marsh soils. Smooth cordgrass
should not be planted outside of the tidal zone. Smooth cordgrass will
tolerate fluctuating water levels. Optimum water depths for establishing
plants are 1" to 18". Plantings in deeper water have been successful,
however plants are slow to anchor and vegetative cover is sparse.
Consequently, plants are more prone to washout, and minimal shoreline
protection is achieved.

Smooth cordgrass is adapted to a wide range of soils from coarse sands
to clays and mucks. Plant establishment and productivity appear to be
superior on heavier mineral soils such as mucky clays, silty clays,
silty clay loams, and fine sands. Soils with very high levels of organic
matter pose structural problems and have proven to be problematic in
establishing stands of smooth cordgrass.

*Considerations*: There are a number of other site-specific elements
that should be considered when working with smooth cordgrass. These
conditions represent extremes and should be thoroughly investigated
prior to committing to a significant project if any of these conditions
occur.

-   Soil load-bearing properties \-- It is not uncommon for soils
    (especially in dredge deposit sites) to be fluid to the point that
    they physically will not support the weight of plants. This is an
    indicator of soils with a very high water-to-mineral ratio.

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-   High organic soils -- Smooth cordgrass will not survive in soils
    with extremely high levels of organic matter. These soils are
    described as having very low bulk density and are problematic. When
    soil texture approaches the consistency of peat moss, there is
    potential for low plant survival.

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-   Poor water circulation -- Smooth cordgrass is critically sensitive
    to sulfide accumulations and has a relatively low tolerance to
    sulfide toxicity.

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-   Shoreline configuration -- Abrupt and steep cut-banks are
    indications of high wave energy and/or highly erodible soils.
    Special precautions may be required to keep transplants from
    dislodging prior to becoming established.

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-   Herbivore grazing -- Smooth cordgrass is a favorite of numerous
    grazing animals. In areas of heavy nutria population, caging plants
    may be required to protect newly planted material.

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-   Smothering -- Precautions should be taken when planting in areas of
    heavy floating debris. Both mechanical damage to the plants from
    surf-trash and smothering from water hyacinths are common.

If any of these conditions are present, consult with a wetland
specialist for additional information and/or possible alternatives.

*Planting*: Smooth cordgrass is a poor seed producer. Although plants
appear to produce a significant number of seeds, most seeds are empty,
damaged, or sterile. Consequently, seed fertility is low. For planting
purposes, two forms of vegetative plant materials are recommended:
containerized and bare-root plugs. Both plant forms have shown to be
equally successful in establishing plant stands when planted properly
and on applicable sites. There are no commercially available sources of
seed, and seeding is not currently a recommended practice.

Smooth cordgrass can be produced in a number of container sizes, however
trade-gallons are the most widely used and most popular size.
Trade-gallon containers have a higher per unit cost compared to smaller
containers or bare-root plugs, but provide the most reliable means of
establishment. Trade-gallon plants have proven to be a highly successful
transplant, especially along shorelines and other areas of high wave
energy.

A trade-gallon will have 5 to 12 aerial stems that are 18" to 24" in
height. Smooth cordgrass produces new tillers (stems) and spreads almost
entirely from rhizomes. Consequently, a well-developed root mass is
critical to the survival and productivity of transplants.

Bare-root plugs are the most economical of the commercially available
plant sizes. Per unit production costs are low and transportation costs
are very low compared to container plants. Bare-root plugs are generally
limited to planting sites that have little or no energy exposure.
Typical sites would include mudflats, sediment disposal areas, terraces,
or other interior and protected sites. Bare-root plugs because of their
limited surface area will not persist in high-energy environments. They
tend to dislodge prior to establishing. Bare-root plugs have
significantly less rootmass than container plants, will suffer a higher
level of transplant shock, and are slower to spread than container
plants. However, if handled properly and used on an applicable site,
bare-root plugs can be highly successful transplants.

Bare-root plugs typically consist of 3 stems 12" to 18" in height, and
stems should remain attached at the root. Plugs should have a rootmass
of at least 2" in diameter at the root crown and 6" of root length.

A complete description (specification) for both trade-gallon container
plants and bare-root plugs is available from the Natural Resources
Conservation Service in Louisiana.

*Planting Date*: As a general rule, smooth cordgrass can be planted
between April 1 to September 30. Some additional considerations include
the following:

-   Smooth cordgrass can be planted anytime past the last frost date if
    there is a need to plant earlier and available transplants are
    actively growing. In some areas this may be earlier than April 1.

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-   In interior marshes with poor water circulation, avoid planting
    between mid-July and the end of August. Elevated water temperatures
    are generally detrimental to new transplants; therefore July and
    August plantings should be limited to lakes, bayous, and other areas
    of frequent tidal exchange.

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-   Late fall plantings in October and November have been successfully
    made in the past, but should be limited to sites that are well
    protected and have minimal winter storm effect.

*Planting Location*: It is critically important to remember that smooth
cordgrass is strictly an inter-tidal plant species and must be planted
within the inter-tidal zone. Smooth cordgrass can be used for erosion
control along shorelines, canal banks, levees, and other areas of
soil-water interface. In addition, smooth cordgrass is an effective soil
stabilizer used on interior tidal mudflats, dredge-fill sites, and other
areas of loose and unconsolidated soils associated with marsh
restoration.

*Shoreline Plantings*: Shoreline plantings are typically planted as a
single row parallel to the shoreline. Transplants should be planted at
the mid-point between the high and low tide elevations. Plant spacing
within the row will vary according to the size of the transplant
materials being used and the rate at which full coverage is desired.
Trade-gallons generally are planted on 5' to 8' centers and plugs
generally on 2' to 3' centers. Under applicable site conditions, smooth
cordgrass will spread laterally filling spaces between plants and will
grow up to its highest elevation and down to its lowest elevation. It is
not uncommon for smooth cordgrass to produce 8' to 10' of lateral spread
in one growing season.

Depending on site conditions and the planting objective, two rows of
smooth cordgrass are occasionally planted. A two-row planting will
provide quicker and denser short-term coverage than a single-row
planting. If two rows are planted, rows should be parallel to each other
and about 5' apart using the same plant spacing within row as that of a
single row. The first row should be placed slightly above the mean tide
elevation and the second row 5' below the first. Plants within the two
rows should be staggered on center so that plants alternate between
spaces.

*Interior Plantings*: In addition to planting shorelines, smooth
cordgrass can also be used along terraces, levees, across mudflats and
dredge-fill sites. The planting configuration should be designed to
provide maximum reduction in fetch lengths. Rows can be placed across
shallow water exchange points to create a passive hydrologic barrier
that will slow tidal exchange and trap suspended sediments. Planting
large areas generally will require a significantly large number of
plants. Where applicable, plugs can be used and placed in a row-column
configuration. The row and plant spacing can vary from a few feet to
many, depending on the objective of the planting, the target rate for
coverage, and available resources.

*Planting Methods*: When planting trade-gallons, transplants should be
planted in a dug hole. Post-hole diggers, gas drills with modified bits,
or any other methods of digging are satisfactory. The planting hole
should be the same size or only slightly larger than the root-ball and
deep enough so that the top of the root-ball is flush or slightly below
ground. The top of the root-ball should not protrude above nor be more
than 2" below normal ground. The planting hole should be tightly closed
around the plant to prevent the plant from wobbling and plants should
remain erect after planting.

Planting sites where high wave energy is a problem may require the
addition of a plant anchor. A plant anchor consists of ¼" mild steel
re-bar bent into a crosier hook (candy-cane shape) and pushed down into
the soil so that hook lays across the root-ball, pinning it to the
ground. Anchors are generally about 30" in overall length and will add
to the cost of the planting. However, anchors are generally necessary at
unusually problematic sites to prevent plants from washing out.

When planting bare-root plugs, holes need only be approximately 3" in
diameter and deep enough to cover the roots. Any style of tool that will
punch a hole this size such as a dibble bar will work. Cupping the roots
of the plug in hand and pushing down into the mud carefully will also
work in more fluid soils. There are no plant anchors for plugs, and in
practice plugs should not be used at any site where wave energy is a
factor.

*Fertilization*: There is no clear consensus on the effectiveness of
fertilizer when used in saturated and/or anaerobic soils. However, the
additional cost of fertilizer is a small investment given the overall
cost involved in vegetative restoration. High nitrogen slow-release
fertilizer tablets will add approximately .08 to .10 cents to the cost
of an individual plant.

Slow-release fertilizer tablets are commercially available in a range of
weights and analyses. Recommended tablet weight should be between 15 and
25 grams and have a nitrogen content of not less than 15% or more than
30%. When using tablets with trade-gallon plants, push the tablet into
the top 3" of the root-ball immediately prior to or immediately after
planting the transplant. The resulting hole should be pinched closed.
When using tablets with bare-root plugs, drop the tablet in the planting
hole prior to inserting the plug.

# Cultivars, Improved and Selected Materials (and area of origin)

There are two known cultivars, 'Vermilion' and 'Bayshore'. Vermilion was
released in 1989 for use in the Gulf of Mexico northern basin, and
Bayshore was released in 1992 for use on the Atlantic Coast. The Natural
Resources Conservation Service Plant Materials Program released both.

Plant materials are generally obtained from two sources, a donor wetland
site or commercial nurseries. The use of donor wetlands to obtain young
plants will eventually affect the health and vigor of the donor stand
regardless of the care taken in frequency, spacing, and location of
plant removal. In addition, the removal of plant materials without the
applicable permits may be in violation of standing state and federal
regulations. Removing plant materials from donor stands is not
recommended.

Nursery-grown stock is generally the most reliable and ecologically
appropriate way to obtain plant materials. There are a number of
commercial nurseries that produce and maintain smooth cordgrass
transplants. Trade-gallon and vegetative plugs are the two most common
sizes, however most nurseries will contract for other container sizes.
Smooth cordgrass seed is currently not commercially available.

Vegetative specifications should be used to tailor plant material
quality and quantity to a specific project. These specifications should
include acceptable sources, cultivars, ecotypes, plant size, stem
height, container specifications, and extent of root development. In
addition, other requirements such as climatic hardening, salt hardening,
procedures for transportation and handling are commonly included.

A list of commercial wetland plant nurseries and assistance in
developing plant material specifications is available from the Natural
Resources Conservation Service in Louisiana.

# References

Alderson, J. & W.C. Sharp 1994. *Grass varieties in the United States*.
Agriculture Handbook No. 170. USDA, SCS, Washington, D.C.

Callaway, J. C., & M. N. Josselyn 1992. *The introduction and spread of
smooth cordgrass (Spartina alterniflora) in south San Francisco Bay*.
Estuaries 15:218-226.

Hitchcock, A.S. 1951. *Manual of the grasses of the United States*.
USDA, Washington, D.C.

Linthurst, R. A., & E. D. Seneca 1980. *Dieback of salt-water cordgrass
(Spartina alterniflora Loisel.) in the lower Cape Fear Estuary of North
Carolina: An experimental approach to reestablishment*. Environ. Cons.
7:59-66.

Texas A&M University 1997. *Grass images*.
\<http://www.csdl.tamu.edu/FLORA/image/poacr2ba.htm\>. Bioinformatics
Working Group, College Station, Texas.

USDA, NRCS 2000. *The PLANTS database*. Version: 000504.
\<http://plants.usda.gov\>. National Plant Data Center, Baton Rouge,
Louisiana.

# Prepared By

## *Mike Materne*, retired

USDA, NRCS, Louisiana State Office, Plant Materials, Baton Rouge,
Louisiana

# Species Coordinator

*Mike Materne*, Agricultural Center, Louisiana State University, Baton
Rouge, Louisiana.

Edited 18sep00 jsp; 14feb03 ahv; 24may06jsp; 080609 jsp

For more information about this and other plants, please contact your
local NRCS field office or Conservation District, and visit the PLANTS
Web site\<[http://plants.usda.gov](http://plants.usda.gov/)\> or the
Plant Materials Program Web site
\<[http://Plant-Materials.nrcs.usda.gov](http://Plant-Materials.nrcs.usda.gov/)\>

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