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Sea Arrowgrass

Triglochin maritima

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Plant Profile

Flowering Months:
Juncaginaceae (Arrowgrass)
Also in this family:
Life Cycle:
Maximum Size:
50 centimetres tall

Green, 3 petals
Tall narrow spike of green flowers on a long stem, 3 petals.
Green, stalked and oblong.
Long and grass-like. Similar to Marsh Arrow-grass but the leaves are unfurrowed and broader.
Other Names:
Coriander Grass, Sea Coriander, Seaside Arrowgrass, Wild Coriander.
Frequency (UK):
Occasionally seen  

Similar Species

Other Information


Triglochin maritima, also known as arrowgrass or seaside arrowgrass, is a perennial plant that is native to Europe and Asia. It belongs to the arrowgrass family and is known for its small, green flowers and linear, grass-like leaves. Triglochin maritima is a low-growing plant that is often found in wetland or coastal areas. It is easy to grow and is tolerant of a wide range of soil types and climates. Triglochin maritima prefers full sun and is drought-tolerant once established. The plant is generally hardy and low maintenance, but it can be prone to pests such as slugs and snails. Triglochin maritima is also known for its medicinal properties and has been used traditionally to treat a variety of ailments. However, more research is needed to fully understand its effects and to determine the safety and effectiveness of using it medicinally.


Sea Arrowgrass, also known as Triglochin maritima, is a perennial herb that is commonly found in coastal areas of the Northern Hemisphere. It is a member of the family Juncaginaceae, which includes other species of arrowgrass found in freshwater and terrestrial habitats.

One of the defining characteristics of Sea Arrowgrass is its long, narrow leaves, which can reach up to 30 centimeters in length. The leaves are typically a bright green color and are arranged in a spiral pattern along the stem. The plant also produces small, inconspicuous flowers that are usually green or brown in color.

Sea Arrowgrass is a highly adaptable plant and can be found in a variety of coastal habitats, including salt marshes, sandy beaches, and rocky shores. It is also a halophyte, meaning that it is able to tolerate salt concentrations that would be harmful to most other plants. This ability allows it to thrive in environments that are often too salty for other plant species.

Sea Arrowgrass is an important plant species in coastal ecosystems. It is a keystone species in salt marshes, providing habitat and food for a variety of animals, such as birds, insects, and small mammals. It also plays a role in stabilizing the soil and protecting the shoreline from erosion.

In addition to its ecological importance, Sea Arrowgrass has also been used for medicinal purposes throughout history. The plant has been used to treat a variety of ailments, including digestive problems and respiratory infections. The root of the plant is believed to have diuretic properties, and has been used to treat kidney and bladder problems.

Overall, Sea Arrowgrass is a versatile and ecologically important plant species that can be found in coastal habitats around the world. Its adaptability to a range of environments and its role in the ecosystem make it an important species to understand and conserve.

Sea Arrowgrass is also known to be a useful plant for cultivation and landscaping. Its ability to tolerate salt and salt spray makes it an ideal plant for coastal landscaping and erosion control. It can be planted along dunes and sea walls, providing natural protection from storm surges and coastal erosion. It can also be used in the landscaping of saltwater marshes, and it can be used to create natural-looking saltwater ponds in gardens.

One of the most interesting things about Sea Arrowgrass is that it's an invasive species in some areas. It can outcompete native vegetation and displace native species, and it can form dense monocultures that can alter the structure and functioning of coastal ecosystems. It is considered invasive in some regions of North America, Europe and New Zealand, and invasive species management programs are in place to control and prevent its spread in these areas.

Sea Arrowgrass is also a valuable food source for wildlife. Its seeds and roots are edible, and they have been used as a food source by indigenous people in the past. It's also a common food for waterfowl, such as geese and ducks, and it's an important food source for saltmarsh-dependent species, such as the saltmarsh sparrow and saltmarsh caterpillar.

Another important aspect of Sea Arrowgrass is its tolerance to environmental stressors, it can tolerate a wide range of salinity, temperatures, and water levels. This makes it a valuable plant for conservation and restoration of coastal habitats, such as salt marshes, dunes, and beaches. Sea Arrowgrass can be used in the restoration of salt marshes, which are important habitats for many species of fish, shellfish, and birds, and also provide important ecosystem services, such as nutrient cycling and shoreline stabilization.

Sea Arrowgrass is also known for its ability to remove pollutants from the environment. It has been shown to be effective in removing heavy metals, such as lead, from contaminated soils. This makes it a valuable plant for phytoremediation, the use of plants to remove pollutants from the environment. This ability of Sea Arrowgrass to remove pollutants makes it a useful tool for restoring contaminated coastal habitats, such as industrial sites and ports.

In addition to its ecological and environmental benefits, Sea Arrowgrass is also a valuable plant for educational and research purposes. Its adaptability to different environments and its ability to tolerate stressors make it an ideal plant for studying the effects of environmental change on coastal ecosystems. It can also be used in educational programs to teach about the importance of coastal habitats and the role of plants in maintaining ecosystem health.

Overall, Sea Arrowgrass is a highly adaptable and valuable plant species with a wide range of ecological, medicinal, horticultural and environmental benefits. It can be used for conservation, restoration, and education and research purposes. However, it is also important to consider its potential as an invasive species and its management. Understanding the different characteristics of Sea Arrowgrass and how it can be used effectively can help to ensure that its benefits can be fully realized while minimizing negative impacts.


Sea Arrowgrass filmed in Sandside, Cumbria on the 13th August 2022.


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Distribution Map

Reproduced by kind permission of the BSBI.

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