Should I Consider Planting a Test Plot of Seashore Mallow in One of My Fields?

Consider Seashore Mallow

1. Can you grow traditional crops successfully everywhere on your farm?

If the answer is yes, don’t consider Seashore Mallow at this stage of its development unless you are interested in broadening your diversity of crops and /or just trying something new. Only recently has the plant from the brackish marshes been studied as a crop and its agronomic qualities are not as “sophisticated” as those of mainline crops, such as soybeans, corn, wheat, etc. That is, yields of grain, knowledge of possible disease and insect pests, shattering issues, and weed control are not as thoroughly researched as with crops that have been in the domestication process for thousands of years. Lines with superior qualities for agricultural products and ecosystem services are just now being identified. Although Seashore Mallow is tolerant saline and wet conditions it doesn’t require then to grow, in fact, it grows well on highly productive soils.
2. If traditional crops cannot be grown because of periodic flooding and /or salinization of the soil due to tidal flooding, Seashore Mallow might be a crop for your future.

Why Mallow? Seashore Mallow is a perennial member of the cotton family that is native to brackish marshes. Its evolutionary adaptations for living in soggy and salty soils, along with those features associated with its ancestral base in Africa, have consolidated in this single species (Kosteletzkya pentacarpos) a number of useful crop plant features. These are combined with features that provide ecological services and resistance to stresses afflicting an increasing number of acres of once productive farmland. These features include: perennial growth habit with older crowns producing multiple stems (~ 10 or more), flood tolerance, drought resistance (deep roots), salt tolerance to half-strength sea water, sorghum sized seeds, seeds with high viability in cold storage (20+ years), high oil content seed (22%), high protein seed meal, long fibers in the outer covering of stems, short light-weight very absorbent fibers in the stem core, flowers that produce abundant nectar, and self-pollinating flowers if pollinators don’t arrive by mid-day. These and other features can be exploited to produce a number of products and ecological services from virtually all parts of the plant. Seashore Mallow is not a “one trick pony.”

3. What specialized equipment is needed to grow and harvest these plants?

Nothing exotic is required. Ordinary farm equipment has been used to grow a three-acre field near Lewes, Delaware. Planting can be done either on traditional-tilled or no-till land with a row planter usually used for soybeans and corn. Sorghum plates handle the seeds very well. Pre-emergent herbicides have been applied as needed with a variety of sprayers. Harvesting has been done either by direct combining or by cutting the crop while it is a little green using a sickle-bar cutter mower/ stem crusher combination with the rollers set apart. After a few days a combine with a pickup head separates the seeds and straw. The straw is then raked into windrows, baled, and hauled to storage. The innovations about how to grow and handle the crop have been made on a farm near Lewes Delaware (Seashore Mallow Harvest photos). Expanding the number of farmers and locations where the plant is growing including farms with storm flood -prone field settings is important to the innovation process as the crop progresses.

4. What are these products and services and who will buy them if I produce them?

There are a number of products and services the plants can provide and they are shown and briefly discussed in the attachment (Economic and Ecological Roles for Seashore Mallow). At the present time there are no commercial operations making these products from the plants although many of the major ones have been produced and evaluated in cooperation with personnel at the USDA, National Center for Agricultural Utilization Research in Peoria, Illinois. Other products are in various stages of development by others as noted in the attachment. Since Seashore Mallow is new to the possible methods of adapting coastal agriculture to sea-level rise, there hasn’t been a supply of the commodity for commercial product production, hence no market at this point. It is anticipated that as a supply of Seashore Mallow raw material expands manufactures will take advantage of the opportunity to produce mallow products. This choice would be made for some products because they have superior qualities to the present feed stocks for similar products. In other cases the “sustainable and green” aspects of Seashore Mallow production (a perennial using soil and irrigation water, neither of which will support traditional crops) enhance the value over those from non-eco-friendly feed-stocks. However, not much can be bought with “anticipated.” Hence, we are seeking funds to offset the expenses of those testing this plant in their fields for production, but none are available at this time.

One ecological service a planting of Seashore Mallow can provides is that of a buffer between field and estuary. It impedes particulate movement and absorbs nutrients thus preventing the lateral movement of nutrients through the soil to adjacent aquatic systems. Since the aboveground plant material is harvested and carried away from the buffer, the zone does not become saturated and “leak” into the adjacent aquatic system. A second service is the storage of carbon below ground in the plant’s large perennial root system. Consequently, the carbon dioxide released into the atmosphere when biodiesel made from the plant’s seeds is burned is recaptured. These services have value for society in general, as well as the farmer and the grower should be compensated for this service. It maybe that one might plant a buffer of Seashore Mallow as part of a Managed Buffer where ecological services were the primary focus and harvesting for products secondary.

5. Would It be better to build a dike around my land, install some drainage channels, and a pump to remove excess rainfall and salty water if the dike is topped or breached during a storm?

It is hard to determine where and how high to build defense structures since it isn’t certain how fast relative sea-level will rise or how severe and frequent storms will come. The type of dike needed will depend on the location and the seaward dike face may be subject to severe erosion during storms unless it is armored. The dike, ditch, and pump solution is expensive and difficult to work around, but dike systems can be made to succeed, as they have from The Netherlands to eastern China and nearby in salt hay fields in New Jersey and rice fields in Georgia.

In addition to achievability, both economic and ecological considerations determine the prudence of construction. It may not be economical in the long term to dike the land and install water management structures if the water level rise is relatively slow and changing to a mallow crop would extend the economic viability of the land use with the right crop for many decades. On the other hand, if the change is very fast, the scale of the diking and water management may need to be so great that is not an economical option. In that case growing mallow for a few decades before letting the land transform into a wetland and perform the ecological functions of a nursery ground for economically important estuarine organisms and other roles wetlands play may be far-sighted. Had the field been diked, seaward wetlands and the services they provide would likely been lost, since with rapid sea level rise the marsh would likely not build vertically fast enough to keep up with sea level rise. In such a case, allowing the eventual transgression of the marsh over the low elevation of the field is a service to society and the farmer should be compensated.

If there are the other questions or points your wish to raise or if you are interested in finding out more about Seashore Mallow as a crop or possibly testing it on you land please contact.

Jack Gallagher ( or Denise Seliskar ( at the Halophyte Solutions Laboratory, Smith Laboratory, School of Marine Science &Policy, College of Earth, Ocean, and Environment, University of Delaware, 700 Pilottown Road, Lewes, DE 19959-1298.

Original Publication Date:

Cooperative Extension Education in Agriculture and Home Economics, University of Delaware, Delaware State University and the United States Department of Agriculture cooperating. Distributed in furtherance of Acts of Congress of May 8 and June 30, 1914. It is the policy of the Delaware Cooperative Extension System that no person shall be subjected to discrimination on the grounds of race, color, sex, disability, age, or national origin.

Disclaimer: Reference to commercial products or trade names does not imply endorsement by University of Delaware Cooperative Extension or bias against those not mentioned.

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