Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide


Batis maritima



Batis maritima (saltwort)


  • Last modified
  • 27 September 2018
  • Datasheet Type(s)
  • Invasive Species
  • Preferred Scientific Name
  • Batis maritima
  • Preferred Common Name
  • saltwort
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Dicotyledonae
  • Summary of Invasiveness
  • B. maritima is a succulent creeping shrub or trailing subshrub up to 1.5 m tall and 2 m or more across. It is a common native in coastal areas of the Americas from California and North Carolina to Peru and Braz...

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Batis maritima (saltwort, pickleweed); habit on sides of dyke. Kanuimanu ponds, Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
CaptionBatis maritima (saltwort, pickleweed); habit on sides of dyke. Kanuimanu ponds, Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
Copyright©Forest Starr & Kim Starr - CC BY 4.0
Batis maritima (saltwort, pickleweed); habit on sides of dyke. Kanuimanu ponds, Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
HabitBatis maritima (saltwort, pickleweed); habit on sides of dyke. Kanuimanu ponds, Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.©Forest Starr & Kim Starr - CC BY 4.0
Batis maritima (saltwort, pickleweed); habit in salty mudflats. Kanuimanu ponds, Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
CaptionBatis maritima (saltwort, pickleweed); habit in salty mudflats. Kanuimanu ponds, Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
Copyright©Forest Starr & Kim Starr - CC BY 4.0
Batis maritima (saltwort, pickleweed); habit in salty mudflats. Kanuimanu ponds, Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
HabitBatis maritima (saltwort, pickleweed); habit in salty mudflats. Kanuimanu ponds, Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.©Forest Starr & Kim Starr - CC BY 4.0
Batis maritima (saltwort, pickleweed); habit. Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
CaptionBatis maritima (saltwort, pickleweed); habit. Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
Copyright©Forest Starr & Kim Starr - CC BY 4.0
Batis maritima (saltwort, pickleweed); habit. Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
HabitBatis maritima (saltwort, pickleweed); habit. Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.©Forest Starr & Kim Starr - CC BY 4.0
Batis maritima (saltwort, pickleweed); habit on mudflats. Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
CaptionBatis maritima (saltwort, pickleweed); habit on mudflats. Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
Copyright©Forest Starr & Kim Starr - CC BY 4.0
Batis maritima (saltwort, pickleweed); habit on mudflats. Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
HabitBatis maritima (saltwort, pickleweed); habit on mudflats. Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.©Forest Starr & Kim Starr - CC BY 4.0
Batis maritima (saltwort, pickleweed); fruiting habit. Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
TitleFruiting habit
CaptionBatis maritima (saltwort, pickleweed); fruiting habit. Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
Copyright©Forest Starr & Kim Starr - CC BY 4.0
Batis maritima (saltwort, pickleweed); fruiting habit. Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
Fruiting habitBatis maritima (saltwort, pickleweed); fruiting habit. Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.©Forest Starr & Kim Starr - CC BY 4.0
Batis maritima (saltwort, pickleweed); big pickles. Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
TitleBig pickles
CaptionBatis maritima (saltwort, pickleweed); big pickles. Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
Copyright©Forest Starr & Kim Starr - CC BY 4.0
Batis maritima (saltwort, pickleweed); big pickles. Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.
Big picklesBatis maritima (saltwort, pickleweed); big pickles. Kealia Pond NWR, Maui, Hawaii, USA. June, 2013.©Forest Starr & Kim Starr - CC BY 4.0


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Preferred Scientific Name

  • Batis maritima L.

Preferred Common Name

  • saltwort

Other Scientific Names

  • Batis americana L.
  • Batis californica Torr.

International Common Names

  • English: American saltwort; beach wort; beachwort; Jamaican samphire; maritime saltwort; pickleweed; samphire; turtleweed
  • Spanish: barilla; hierba de vidrio (Cuba); lechuga de mar; perejil de costa (Cuba); planta de sal; saladilla; verdolaga rosada
  • French: herbe-à-crâbes; soude des Antilles

Local Common Names

  • Mexico: paxoocsim; saladilla; xpaxoocsim
  • USA/Florida: pickleweed
  • USA/Hawaii: ‘akulikuli kai

EPPO code

  • BAGMA (Batis maritima)

Summary of Invasiveness

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B. maritima is a succulent creeping shrub or trailing subshrub up to 1.5 m tall and 2 m or more across. It is a common native in coastal areas of the Americas from California and North Carolina to Peru and Brazil. It is a pioneering species especially after storms and hurricanes, where it then helps coastal trees such as mangroves to become established. It has been recorded as invasive only in Hawaii, where it is a difficult to eradicate environmental weed. It has also been widely introduced in species trials as a potentially valuable halophyte for growing with seawater irrigation, but it appears not to have become naturalized elsewhere.

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Plantae
  •         Phylum: Spermatophyta
  •             Subphylum: Angiospermae
  •                 Class: Dicotyledonae
  •                     Order: Capparidales
  •                         Family: Bataceae
  •                             Genus: Batis
  •                                 Species: Batis maritima

Notes on Taxonomy and Nomenclature

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B. maritima is one of only two species in the genus Batis, the other being B. argillicola P.Royen, and Batis is the only genus in the family Bataceae (The Plant List, 2013; USDA-ARS, 2015). The species was described by Linnaeus, and has remained a ‘good’ and clearly delimited species since, without any taxonomical issues.

Study of the wood anatomy by McLaughlin (1959) also concluded that there were only two species in the genus and in the family, being a taxonomically isolated and reduced family that should also be placed in an order by itself, the Batidales, considered as allied to the Centrospermae.

As the Greek word batis means "prickly roach" or "large spiky fish", the plant genus name Batis is thought to be derived from an ancient Greek name quoted by Pliny (AD 23-79) for an (unidentified) seacoast plant (Austin, 2004).

Batis is also a genus of bird. 


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B. maritima is a succulent creeping shrub or trailing subshrub, 1-1.5 m tall and 2 m or more across, with a woody base up to 5 cm in diameter. Bark greyish white, stem wood weak and brittle. Multiple stems growing from the root crown, as they become tall and heavy, tend to lie down and root along the stems forming loose mats. Branches prostrate to ascending, often (3)4(5)-angled. Leaves simple, opposite, succulent, nearly cylindrical, 2.5 cm long, margins entire, no petioles, sessile, stipules minute and caduceus. Sap is salty, smelling a little like vinegar. Tiny, white male and female flowers occur on different plants. Flowers unisexual, in small, green, cylindrical to strobiloid, axillary or terminal spikes or clusters, each flower initially enclosed by a membranous saccate organ (perhaps calyx or bracteoles) that eventually splits into 2 or 4 lobes or only along one side; perianth parts 4, distinct (sometimes considered to be staminodes), absent in female flowers; stamens 4, alternate with the perianth; anthers dithecal, opening by longitudinal slits; gynoecium vestigial in male flowers, in female flowers the superior ovary 2-carpellate, 4-celled, the 2 primary cells each divided by a partition from the carpel midrib to the central axis, placentation parietal-basal, ovules 1 per cell, anatropous; stigmas 2, sessile. Fruit axillary drupaceous, 1-2 cm long and seeds without endosperm and perisperm, both adapted to dispersal by flotation in salt water (adapted from Wiggins and Porter, 1971; Liogier, 1985; Wagner et al., 1999; Motooka et al., 2003).

Plant Type

Top of page Perennial
Seed propagated
Vegetatively propagated


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B. maritima is predominantly a tropical and subtropical American coastal species, native to a large area on both eastern and western seaboards from approximately 35ºN to 10ºS. On the Pacific coast, it is found from California to Peru, including the Galapagos Islands (PIER, 2015), and on the east coast, from North Carolina south to Florida and around the Gulf of Mexico, throughout the Caribbean, and along northern South America to the north east of Brazil (USDA-ARS, 2015).

Neal (1965) states that it has been planted in a number of areas in the tropics and has naturalized in at least Hawaii. However, it appears that B. maritima has been reported as naturalized only in Hawaii, where it is widespread and a known invasive (Wagner et al., 1999). What is clear, however, is that it was already widespread and well naturalized in Hawaii by the late 1800s (Guppy, 1906), and was thus likely introduced long before this time.

B. maritima is also mentioned in a number of research reports as a potentially valuable halophyte for introduction to coastal arid areas in the Middle East and elsewhere in Asia, and for use in plantations using saline water irrigation; it is assumed to have been introduced as part of species trials although it is not known whether the species has naturalized in any of those locations. It is not present in Europe (Royal Botanic Garden Edinburgh, 2015) or Australia (Council of Heads of Australasian Herbaria, 2015).

The only other species in the genus and in the family, B. argillicola, has an entirely separate native range in northern Australia (northern/coastal areas of Western Australia, Northern Territory and Queensland), approximately 120-145ºE, and the south central coast of the island of New Guinea (Irian Jaya, Indonesia, and Papua New Guinea) (Council of Heads of Australasian Herbaria, 2015; USDA-ARS, 2015).

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

North America

MexicoPresentNativeUSDA-ARS, 2015Coastal
USAPresentPresent based on regional distribution.
-AlabamaPresentNativeUSDA-NRCS, 2015Coastal
-CaliforniaPresentNativeUSDA-NRCS, 2015Coastal
-FloridaPresentNativeDebez et al., 2010; Council of Heads of Australasian Herbaria, 2015; USDA-NRCS, 2015Coastal
-GeorgiaPresentNativeUSDA-NRCS, 2015Coastal
-HawaiiPresentIntroduced Invasive USDA-NRCS, 2015Coastal
-LouisianaPresentNativeUSDA-NRCS, 2015Coastal
-MississippiPresentNativeUSDA-NRCS, 2015Coastal
-North CarolinaPresentNativeUSDA-NRCS, 2015Coastal
-South CarolinaPresentNativeUSDA-NRCS, 2015Coastal
-TexasPresentNativeUSDA-NRCS, 2015Coastal

Central America and Caribbean

AnguillaPresentNativeUSDA-ARS, 2015Coastal
Antigua and BarbudaPresentNativeUSDA-ARS, 2015Coastal
BahamasPresentNativeUSDA-ARS, 2015Coastal
BelizePresentNativeUSDA-ARS, 2015Coastal
British Virgin IslandsPresentNativeUSDA-ARS, 2015Coastal
Cayman IslandsPresentNativeUSDA-ARS, 2015Coastal
CubaPresentNativeUSDA-ARS, 2015Coastal
Dominican RepublicPresentNativeUSDA-ARS, 2015Coastal
GrenadaPresentNativeUSDA-ARS, 2015Coastal
GuadeloupePresentNativeUSDA-ARS, 2015Coastal
HaitiPresentNativeUSDA-ARS, 2015Coastal
HondurasPresentNativeUSDA-ARS, 2015Coastal
JamaicaPresentNativeUSDA-ARS, 2015Coastal
MartiniquePresentNativeUSDA-ARS, 2015Coastal
NicaraguaPresentNativeUSDA-ARS, 2015Coastal
PanamaPresentNativeUSDA-ARS, 2015Coastal
Puerto RicoPresentNativeUSDA-NRCS, 2015Coastal
Saint Kitts and NevisPresentNativeUSDA-ARS, 2015Coastal
Trinidad and TobagoPresentNativeMissouri Botanical Garden, 2015Coastal
United States Virgin IslandsPresentNativeUSDA-ARS, 2015Coastal

South America

BrazilPresentNativeUSDA-ARS, 2015North coastal
-CearaPresentNativeTanaka and Maia, 2006
-Rio Grande do NortePresentNativeMissouri Botanical Garden, 2015Coastal
ColombiaPresentNativeUSDA-ARS, 2015Coastal
EcuadorPresentNativeUSDA-ARS, 2015Coastal
-Galapagos IslandsPresentNativeUSDA-ARS, 2015Coastal
GuyanaPresentNativeUSDA-ARS, 2015Coastal
PeruPresentNativeUSDA-ARS, 2015Coastal
SurinamePresentNativeUSDA-ARS, 2015Coastal
VenezuelaPresentNativeUSDA-ARS, 2015Coastal

History of Introduction and Spread

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The first report of B. maritima in Hawaii is apparently from 1859 on Sand Island, Honolulu, Oahu, from where it has spread, becoming common in coastal areas, brackish ponds and marshes on all the Hawaiian islands (Motooka et al., 2003).

It is speculated that plants or plant parts were carried to the Galapagos Islands from South America by ocean currents (Trillmich, 2002) and so B. maritima may be considered as naturalized there, although it may be a relatively recent arrival.

Risk of Introduction

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Noting the potential for long-distance oceanic dispersal, there is a risk of natural spread throughout the Pacific over time, but it is much more likely that this could be facilitated by human-induced vectors, such as plant parts becoming attached to boats or other maritime equipment.

There are numerous records of the intentional introduction of B. maritima for species trials of halophytes that could be used in arid coastal areas with seawater irrigation, and further trials may be established in the future. However, there are no records of naturalization that have resulted from such introductions.


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B. maritima is a coastal species where it may become abundant and form dense colonies in salt marshes, brackish marshes, at the upper edges of tidal flats, on the margins of salt pans and wind-tidal flats, and in mangrove swamps between scattered mangroves at the edge of denser mangrove stands, but rarely occurs in sites subject to sand coverage. It typically occurs at elevations less than 1 m above mean sea level and where salinity ranges from 18 to 50 ppt (Lonard et al., 2011). It is known as a pioneer species after mangroves are destroyed by storms or hurricanes. Where it has become naturalized in coastal areas of Hawaii, it is common along coastal areas in brackish ponds and marshes and on saline soils (Wagner et al., 1999).

Habitat List

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Terrestrial ‑ Natural / Semi-naturalArid regions Present, no further details Productive/non-natural
Coastal areas Present, no further details Harmful (pest or invasive)
Coastal areas Present, no further details Natural
Mangroves Present, no further details Harmful (pest or invasive)
Mangroves Present, no further details Natural
Mud flats Present, no further details Harmful (pest or invasive)
Mud flats Present, no further details Natural
Intertidal zone Present, no further details Harmful (pest or invasive)
Intertidal zone Present, no further details Natural
Salt marshes Present, no further details Harmful (pest or invasive)
Salt marshes Present, no further details Natural

Biology and Ecology

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The chromosome number is reported as 2n = 22 (Goldblatt, 1976).

Reproductive Biology

B. maritima is a perennial, dioecious plant (Wagner et al., 1999), and is probably wind pollinated. It has pistillate inflorescences that provide several pollen receptors over their surface and that also function as units for dispersal, probably using sea currents and tides (Ronse de Craene, 2005). It is a profuse seed bearer (Marcon, 2003). Most effective reproduction of the species may be vegetative,  particularly via broken plant parts carried by water. Sprouting from the root crown occurs with and without disturbance, and layering appears to be a continual process with prostrate stems.

Physiology and Phenology

B. maritima is a C3, dioecious, halophytic, succulent shrub that grows in salt marshes and salt flats (Marcon, 2003). It is an obligate halophyte requiring high salt concentrations for optimal growth, and can survive extreme salinity over long periods due to its ability to use sodium for osmotic adjustment, selective absorption of potassium ions over sodium ions, and the absence of photosynthetic pigment degradation (Debez et al., 2010). B. maritima also manages salts by sequestering them in cell vacuoles and eventually shedding the leaves. As such, leaf succulence also increases significantly in the dry season when leaves are shed, reducing salt-induced stress (Lonard et al., 2011), and leaf succulence increases as much as 1.5 times during the dry season to maintain a near static solute concentration (Lüttge et al., 1989).

B. maritima was grown experimentally in the UAE along with a number of other halophytic species, and dry matter yields were not affected significantly by salinity up to 20 g/litre, but significant reduction was seen with salinity up to 40 g/litre (El-Haddad and Noaman, 2001). In Morocco, in concrete pounds filled with coastal sand and watered with 25-100% seawater, B. maritima grew in full strength seawater in spite of the low nutrient content (Harrouni et al., 1999).

B. maritima grew 65 cm with dry weights of 120 g in 3 months when planted as cuttings and irrigated with fresh and brackish water, but less so when more seawater was used (Miyamoto et al., 1996). Wild plants in the native range in Puerto Rico extend stem lengths by about 1 m per year (Lüttge et al., 1989). Probably all planting for landscaping and environmental restoration is by rooted cuttings or uprooted wild plants, except in Hawaii where it is being controlled as an invasive weed. It grows in disturbed areas where few other plants can survive. The use of seawater directly to irrigate halophyte crops is described by Glenn et al. (1995).

B. maritima flowers in the spring and fruits in the summer in Florida (Long and Lakela, 1976), but flowering and fruiting are reported all year round in Puerto Rico, and it is likely that this is also the case in all truly tropical regions where it occurs.


Mangrove vegetation on the northern coast of Cuba is represented by B. maritima with Conocarpus erectus and Laguncularia racemosa, with the bush communities Surianetum maritimae and Tournefortietum gnaphalodes nearest the beach, behind which is low forest dominated by Coccoloba uvifera (Samek, 1973).

In Florida lagoons, shorelines commonly contain B. maritima and Sarcocornia perennis, and can trap seeds of the mangrove Rhizophora mangle (Donnelly and Walters, 2014). Black mangrove (Avicennia germinans) seedlings are also found in increased numbers in established B. maritima stands (Milbrandt and Tinsley, 2006).

Disturbance is an important factor influencing plant species composition and diversity. At a non-tidal salt marsh site in Baja California, Mexico, seven species including annuals, short- and long-lived perennials, ephemerals and parasites were lost due to tidal exclusion, with the perennials B. maritima and Sarcocornia pacifica remaining as dominants. However, species-rich communities developed in diked estuaries (Ibarra-Obando et al., 2010). B. maritima cover also increased temporarily after periods of consistent rainfall, though the response was short term and cover quickly returned to pre-inundation conditions within 3 months. However, prolonged freshwater inundation can lead to long-term (>2 years) decreases in percent cover of B. maritima in salt marshes (Alexander et al., 2002).

The mycorrhizal status of dune plants from Hawaii was investigated and the presence of VAM fungi in dunes may be of critical importance for successful colonization by some vascular plants, and these fungi may thus have influenced the subsequent development of native flora (Koske, 1988).

Environmental Requirements

B. maritima is native to tropical and subtropical climates in the Americas, and is found along coastlines independent of annual rainfall, as groundwater is always available. It is present in western coastal areas where annual rainfall may be as low as 100 mm, or in areas with 30 times that amount or more.

Also, although it is not a water-loving plant, it can endure brief flooding and long periods of waterlogged soils (Nelson, 1996). B. maritima grows slowly in soils with high salt concentrations and areas with seawater overwash, where it suffers little competition from other plants. It also grows in soils without salt but is vulnerable to competition from non-halophytes in such areas. It is commonly found in what are usually sandy, marly or gravely soils, and deposits of dead plant material at high tide marks appear to be beneficial to establishment and growth (Pennings and Richards, 1998). B. maritima is intolerant of shade, and is not seriously affected by insects, diseases or grazing.


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Af - Tropical rainforest climate Preferred > 60mm precipitation per month
Am - Tropical monsoon climate Preferred Tropical monsoon climate ( < 60mm precipitation driest month but > (100 - [total annual precipitation(mm}/25]))
As - Tropical savanna climate with dry summer Preferred < 60mm precipitation driest month (in summer) and < (100 - [total annual precipitation{mm}/25])
Aw - Tropical wet and dry savanna climate Preferred < 60mm precipitation driest month (in winter) and < (100 - [total annual precipitation{mm}/25])
BS - Steppe climate Preferred > 430mm and < 860mm annual precipitation
BW - Desert climate Preferred < 430mm annual precipitation
Cf - Warm temperate climate, wet all year Preferred Warm average temp. > 10°C, Cold average temp. > 0°C, wet all year
Cs - Warm temperate climate with dry summer Preferred Warm average temp. > 10°C, Cold average temp. > 0°C, dry summers
Cw - Warm temperate climate with dry winter Preferred Warm temperate climate with dry winter (Warm average temp. > 10°C, Cold average temp. > 0°C, dry winters)

Latitude/Altitude Ranges

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Latitude North (°N)Latitude South (°S)Altitude Lower (m)Altitude Upper (m)
35 10


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ParameterLower limitUpper limitDescription
Dry season duration012number of consecutive months with <40 mm rainfall
Mean annual rainfall503500mm; lower/upper limits

Rainfall Regime

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Soil Tolerances

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Soil drainage

  • free
  • impeded
  • seasonally waterlogged

Soil reaction

  • acid
  • alkaline
  • neutral

Soil texture

  • heavy
  • light
  • medium

Special soil tolerances

  • infertile
  • saline
  • shallow
  • sodic

Natural enemies

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Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Armases cinereum Herbivore Leaves not specific Goranson et al., 2004
Ascia monuste Herbivore Leaves Goranson et al., 2004
Brephidium isophthalma Herbivore Leaves Lonard et al., 2011
Orchelimum fidicinium Herbivore Leaves Goranson et al., 2004
Orphulella pelidna Herbivore Leaves Goranson et al., 2004
Paria aterrima Herbivore Leaves Goranson et al., 2004
Paroxya clavuliger Herbivore Leaves Goranson et al., 2004
Sparganothis Herbivore Leaves Goranson et al., 2004

Notes on Natural Enemies

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Six common leaf-chewing herbivores were found feeding on B. maritima in Georgia and Texas, USA, by Goranson et al. (2004): Armases cinereum, Orchelimum fidicinium, Orphulella pelidna, Paroxya clavuliger, Paria aterrima and Sparganothis sp. In addition, Moon and Moon (2010) assessed the impacts of caterpillars of the lepidopteran herbivore Ascia monuste, and its primary parasitoids and hyperparasitoids.

Means of Movement and Dispersal

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Natural Dispersal

B. maritima fruit is drupaceous, and appears to be adapted to dispersal by flotation in salt water. However, most effective reproduction appears to be vegetative, with sprouting from root crowns, layering, and new plants started by cuttings and broken plant pieces. Water still seems to be the principal means of dispersal, whether as seeds or via vegetative means. The following, written more than a century ago in Hawaii (Guppy, 1906), summarizes well how B. maritima disperses naturally:

"When in Hawaii I made some observations on the germination of Batis maritima in seawater, a plant with which I was also familiar in its home in the salt water pools of the coast of Peru. The mature fruits on being freed from the parent plant in sea water float away and in from one to two weeks they break down from decay, setting free the seeds. The seeds float in sea water indefinitely, their buoyancy only terminating with their germination, the first seeds germinating afloat about six weeks after the breaking down of the fruit whilst the rest continue to float in the sea water during the next three months, some of them germinating at intervals and all of them doing so eventually. Strange to say, although the seedlings remained healthy whilst afloat in the sea water they made no effort either to separate the cotyledons or to produce a plumule."

Accidental Introduction

B. maritima propagates vegetatively and by seed, and it is reported that plant parts can be carried to new habitat by machinery as well as by water and possibly by attachment to boats.

Intentional Introduction

B. maritima is noted as having some ornamental value, and appears to be especially valuable in successions, as it aids the establishment of mangrove trees, in rehabilitating coastal areas. It has also been introduced as a potentially valuable halophyte for growing in plantations with seawater irrigation, notably in North Africa and the Middle East. Thus, it has already been introduced intentionally, and it is likely that further intentional introduction will occur.

Pathway Causes

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CauseNotesLong DistanceLocalReferences
Crop production Yes
Disturbance Yes
Flooding and other natural disasters Yes

Pathway Vectors

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VectorNotesLong DistanceLocalReferences
Floating vegetation and debris Yes Yes
Machinery and equipment Yes
Water Yes Yes

Impact Summary

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Environment (generally) Positive and negative

Environmental Impact

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Positive environmental impacts include the cover and nesting sites that B. maritima provides for some species of birds, and serves as the larval and adult hosts for the great southern white (Ascia monuste) and eastern pygmy blue (Brephidium isophthalma) butterflies. It is an important food source for the Galapagos marine iguana (Amblyrhynchus cristatus) (Lonard et al., 2011), but due to high levels of glucosinolates in plant tissues, it is unpalatable as a fodder to most other large vertebrates.

In Hawaii, mangroves (Rhizophora spp.) and pickleweed (B. maritima) invade together, displacing native vegetation, choking open water and the mudflats used by waterbirds, trapping sediment, and negatively affecting water quality and hydrology (Rauzon and Drigot, 2003). Waterbirds such as the Hawaiian black-necked stilt (Himantopus mexicanus knudseni) and Hawaiian coot (Fulica alai) are endangered and most restoration projects focus on designing and managing habitat for these endangered species. Much less attention has been given to native wetland plants, potentially because high vegetative cover is often not appropriate to maximize habitat use by Hawaiian waterbirds.

B. maritima is reported as naturalized by USDA-ARS (2015), a weed (Holm et al, 1979) and an agricultural weed where native (Acuna, 1974) and an environmental weed where introduced (Motooka et al., 2003). In Hawaii wetlands, reported impacts are almost entirely negative, with Motooka et al. (2003) noting that B. maritima tends to smother low-growing native plant species in coastal areas and in anchihaline ponds. Rauzon and Drigot (2003) report the impacts of B. maritima and red mangrove (Rhizophora mangle), another exotic invasive species affecting similar habitats, in a 195-hectare wildlife management area and historic Hawaiian fishpond complex, home to approximately 10% of Hawaii's endemic and endangered population of black-necked stilt and at least 16 species of native fish. These invasive plants were observed to be changing the ecology and character of the fishponds from a native Hawaiian structure to one that had more similarities to Florida.

Risk and Impact Factors

Top of page Invasiveness
  • Invasive in its native range
  • Proved invasive outside its native range
  • Has a broad native range
  • Abundant in its native range
  • Pioneering in disturbed areas
  • Highly mobile locally
  • Long lived
  • Has high reproductive potential
  • Reproduces asexually
Impact outcomes
  • Modification of successional patterns
  • Monoculture formation
  • Reduced native biodiversity
  • Threat to/ loss of endangered species
  • Threat to/ loss of native species
Impact mechanisms
  • Competition - monopolizing resources
  • Rapid growth
Likelihood of entry/control
  • Highly likely to be transported internationally accidentally
  • Highly likely to be transported internationally deliberately
  • Difficult/costly to control


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B. maritima is a promising halophyte for sand-dune stabilization, saline-soil reclamation, and also for producing animal feed (Glenn et al., 1995). The species also has applications in herbal medicine and as an oilseed crop (Debez et al., 2010). B. maritima is used as an ornamental and ground cover, and has environmental benefits as it covers and protects salty coastal areas where few other species can grow, and its extreme salt tolerance allows it to be irrigated with brackish water and seawater (Miyamoto et al., 1996). Ashes of the plant were once also used in the manufacture of glass and soap. The leaves are sometimes eaten as a salad (Neal, 1965). Where native, it also has some traditional food uses, for example, leaves and seeds are added to salads, used as a pot herb, puree or pickle (Austin, 2004), seeds can be toasted or popped like popcorn, and roots were used as a sweetener before the arrival of refined sugar (Felger and Moser, 1985). It has also been used in folk herbal medicine to treat a number of ailments including skin and blood disorders (Liogier, 1990).

The seed is a rich source of nutritionally important protein (17%) and oil (25%), and of the total seed protein, 87% is a unique, highly soluble globulin storage protein rich in essential amino acids such as lysine and methionine and with little trypsin inhibitor activity (Marcon, 2003). The oil fraction was found to be of high quality, highly nutritious, with a very high degree of unsaturation (93%). Its fatty acid profile is almost identical to that of safflower oil, but is much richer in lipid soluble antioxidants. Its extremely small starch grains could provide unique functional properties in some food and non-food applications such as food thickeners, paper coatings, laundry starch, dusting powders, cosmetics, fat replacers, and thickeners in the printing of textiles and biodegradable plastics (Marcon, 2003).

Uses List

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Animal feed, fodder, forage

  • Fodder/animal feed
  • Invertebrate food


  • Amenity
  • Erosion control or dune stabilization
  • Land reclamation
  • Revegetation
  • Wildlife habitat

Human food and beverage

  • Food additive
  • Oil/fat
  • Seeds
  • Sweetener
  • Vegetable


  • Oils

Medicinal, pharmaceutical

  • Traditional/folklore

Prevention and Control

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Physical/mechanical control

In Hawaii, B. maritima plants are pulled up by hand, and any resprouts can be treated with a propane torch (Motooka et al., 2003). Areas of B. maritima are also annually ploughed using amphibious assault vehicles in military areas in Hawaii, especially for waterbird conservation near established breeding areas (Rauzon and Drigot, 2003), but after 20 years of effort with thousands of volunteer hours and more than US$2.5 million of contracted labour costs, only some 8 hectares of mangrove were removed.

Biological control

There have been no attempts at investigating biological control options for B. maritima.

Chemical control

Herbicides have been tested (Ansari and Thair, 2012), and B. maritima has proved sensitive to foliar applications of triclopyr ester (especially with an oil carrier), glyphosate and sulfometuron, and to soil applications of bromacil and hexazinone. Good control of resprouts has been achieved with glyphosate applied to wet the foliage (Motooka et al., 2003).


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01/04/2015 Original text by:

Nick Pasiecznik, Consultant, France

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