2 � 3 faat spacingRetie plants

By Arnold C. LaneRegional See Grant Extension Specialistand

Andrew i. Gutman, Coasta! EngineerExtension Sea Grant Advisory Program Staff

One of the most serious threats to waterfront property is ero-

sion, Often the very body of water which makes the aesthetic and

dollar value of your frontage property so high can greatly damage

your land. Property owners may take steps to prevent erosion,

but often these steps are costly, require expensive equipment and

highly skilled labor, and involve structural methods which may or

may not be successful,

ln a sheltered waterfront area such as a bay, river, or estuary,

the property owner has another option. Salt marshes are a non-

structural, environmentally sound alternative for preventing or

reducing erosion. By planting Spartina alterni flora marsh grass!in the intertidal zone between the high and low watermarks, you

can establish a man-made marsh. This stabilizes the intertidal zone

and thereby creates a buffer effect.

A healthy salt marsh combats shoreline erosion in three ways:� The root system of the marsh grass binds sail and prevents

material from being washed out by waves and tidal currents.� A marsh dissipates the action of waves as they reach the

shoreline, thus reducing their impact and ability to erode,

� Silt and sand transported by water is trapped in the marsh;this raises the elevation of the intertidal area and eventually

prevents waves from breaking right on the shoreline.

A great deal of research, primarily by Drs. W.W. Woodhouse,E.D. Seneca, and S,W, Broome of North Caroline State University,with support from the U.S, Army Corps of Engineers and theNational Oceanic and Atmospheric Administration's Sea GrantProgram, has led to the development of guidelines for choosingappropriate sites and planting techniques for S. alternif lore.

conti nued J

Site SelectionThree mojo~ factors to consider when deciding whether or not

to plant marsh grass are tidal range, wave activity, and saliriity. If

these conditions are not favorable, the marsh wgl have a limited

chance ot survival,

Tidal Range; Identifying the proper tidal elevation zone for

growing S, alterniffora is crit!cal. Go~orally, in areas with a smalltidal range less than three or four feet! the marsh can grow be-tween Meari Low Water MLW! and IVlean High Water MHW!.

However, in areas with a larger tidal range, the marsh wilI survive

only between Mean Sea Level MSL! and MHW. The upper andlower limits ot growth can be estimated by checking nearby es-

tablished stands of marsh grass or by using the rule of thumb

above.

if!lave Activity: Salt marshes are usually viable in areas which

are exposed only To low wave action. The larger the distance ofopen water called offshore tetch!' over which the wind can blow

to generate waves, the more intense wave conditions will be at

the shoreline.Salinity: The remaining physical factor in the suitability of a

site for planting is the salinity of the soil, or substrate. If you donot plan to transplant from a nearby site with similar soil, have

your soil tested for salinity by a laboratory. S. alterniflora willtolerate a wide range of salinity, from nearly fresh to very salty�,5 to 42.5 parts per thousand! soil solutions, Salinities of the

soil solution exceeding 45 parts per thousand can cause diebackof the leaves and sometimes ot the entire p!ant, High salinity also

prevents seeds. from forming in the plants, and so all planting in

areas with salinity greater than 20 parts per thousand should bewith transplants,

Planting TedtnitluesS. alternif lore can be started from sprigs, plugs, seedlings, and

seeds,A sprig is part of the plant consisting of at least one node joint

of a stem from which leaves arise! with attached stems and roots,

A plug is a mass of roots and stems with their original soil, Both

are gathered by digging in a healthy existing marsh. However, youmust exercise caution to avoid damaging the marsh during this

procedure,Mtz ~crt dig- in "areas "sub1ect to eroslorri." Digging arid"

separating planting stork is easiest from a sandy substrate or from

young marshes which lack a thickly developed root system. If pos-

sible, dig from a stand located near the new planting site in order

to minimize salinity change for the transplants.

The sprigs or plugs shoukd be stacked roots down in tubs or

buckets and kept moist until planting, Material that cannot be

planted within a day or two should be heeled-in in trenches within

the intertidal zone. You can gather transp!ants by hand with shov-

els in small areas or by backhoe for larger projects, lV!ake your

holes arid then set the sprigs or plugs to a depth of tour to six

inches with the: soil firmed around them. Place them in staggered

rows, with two ta three feet of spacing between plants. Exper-

ience has shown that plugs transplanted at exposed sites or with

inadequate site preparation can be subject to washout by wave

action. In more exposed sites, place the plants closer together.

Hand transplanting S. aiternitlora invoh es openfrrg a hole with a

dibble and inserting a single healthy sfem to a depth of 4-6 inchesand firming the soil around it. Photo courtesy of Ififoodhouseet al,l

S. alrernif lore can also be propagated by seeds. Usually, seeds

can be harvested from existing stands during September and Octo-ber by cutting the seed heads from the mature plants. They should

then be stored for two weeks in a moist rondition and afterward

in cold, brackish water until the spring. Seeds should then be

broadcast at about 100 seed» per square yard at low water and

covered To a depth af one. half inch, Seeding should be used only

for very protected shorelines with low salinity. Any wave act~on

will wash out the seeds. The seeding method will take longer for

marsh development than transplanting techniques,

The Standing Crap Of abOve. grOund growth of S alrernifloiacan be increased significantly be adding fertilizer. About 100'pau'rids of riitrogen per aacre is recommended at the time of plant-ing and an equal amount one month later, Ammonium sulphateshould be used if possible because the ammonium torm of nitro-

geri seems rtiost suitable for the rnarSh environment.

April ond IVlay are the best months for transpionting, but suc-

cessful planting ran be done throughout most of the year. Devel-

opment ot transplanted or seeded areas is rapid. After Two growing

seasons, you will detect little difference in appearance and primary

productivity ot the vegetation between your artifically propagated

marsh and ong-established natural marshes.

8EFORE: At Bogue

Sound, IVorth Caro-

h'na, S. alterniflora

was plantedin April,

f974. The tidal range

thereis 2y~ feet, and

the offshore fetch is

less than four miles,

AFTER: The carne

location each;'bi ted a

healthy salt iriard! in

October, 1975, or

three growing sea-

sons la ter. Photos

courtesy of Wood-house. eI al,!

lf you desire more information about starting new areas of

marsh grass, contact the Cape Cod Extension Service, Barnstable,MA 02630 f Tel. 617-362-2511, ext. 201I. Some additional refer-

ences on arti fi cially propagating marshes:

This pamphlet is available from Massachusetts Extension Sea

Grant Advisory Program staff:

ISSuad by the COOperatiVe EXtenaiOn ServiCe, ROSS. S, Wheley, DireCtOr, in furtheranCe Of the ACtS Of May 8 and June 30, 1914; UniVeraity Of MaSSaChu-setts, United States Department of Agriculture and Coumy Extension Services cooperating. The Cooperative Extenfion Service of fers equal opportunityin programs and employment. BI79 � 2M

POSTAGE ANO FEES PAIDU.S. DEPARTMENT OF

AG RIG ULTU R E

Cooperatrve Extension ServiceUniversity of MassachusettsAmherst, Iylassachusetts 01003R.S. Whaley, DirectorCooperative Agricultural ExtensionWorks Acts of Iylay 8 and June 30, 1914

AGR 101

Official BusinessPENALTY FOR PRIVATE USE, $300

"Propagation of Spartina alterniflora far Substrate Stabilizationand Salt Marsh Development. " Prepared by; W.W. Woodhouse,Jr., E.D. Seneca and S.W. Broome, Technical Memorandum No.

46. August 1974. Coastal Engineering Research Center CERCJ,U.S. Army Corps of Engineers, Kingman Building, Fort Belvoir,VA 22060."Marsh Building with Dredge Spoil in North Carolina. "Bulletin445, North Carolina Agricultural Experiment Station, NorthCarolina State University, Raleigh, NC 27607. July 1972. Avail-

able from the National Technical Information Service as CERC

Reprint R2-72!, W.W. Woodhouse, Jr., E.D. Seneca and S.W.Broom e.

"Propagation of Smooth Cordgrass S, aiterriiflora from Seedin

North Carolina." Chesapeake Science, Vol. 15, No. 4, December197e. S. W, Broome, W, W. Woodhouse, Jr. and E,D, Seneca.

Ralph H. Goodno, Regional Extension Sea Grant Specialist, Essex

Agricultural and Technical Insti tute, 562Maple Street, Hawthorne,MA 01937.

Arnold C. Lane, Regional Extension Sea Grant Specialist, CapeCod Extension Service, Deeds and Probate Building, Railroad

Avenue, Barnstable, MA 02630.

Michael Si kore, Jr., Regional Extension Sea Grant Specialist,

Plymouth County Extension Service, High Street, Hanson, MA02341,

Information Center, Massachusetts Institute of Technology SeaGrant Program Office, Room E38-302, 77 Massachusetts Avenue,

Cambridge, MA 02139.