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Sea Spleenwort

Asplenium marinum

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Plant Profile

Aspleniaceae (Spleenwort)
Life Cycle:
Maximum Size:
30 centimetres tall
Cliffs, gardens, rocky places, sea cliffs, seaside, walls.
Ferns do not produce flowers.
The spores are ripe in every month in the British Isles, except for mid-July to mid-August.
1-pinnate, oblong leaves (fronds). The leaflets are oval. Bright green, leathery, tufted leaves (fronds). Often found growing in the cracks of walls and cliffs that are exposed to sea spray. Evergreen. Similar in appearance to Maidenhair Spleenwort (Asplenium capillus-veneris) and Green Spleenwort (Asplenium viride) but Sea Spleenwort is a maritime plant with longer leaves (and leaflets).
Other Names:
Rock Spleenwort.
Frequency (UK):
Occasionally seen  

Similar Species

Other Information


Asplenium marinum, also known as sea spleenwort, is a fern species native to coastal areas of Europe and North Africa. It typically grows in rocky crevices and can tolerate salt spray and high winds. It is a small, evergreen fern that forms rosettes of triangular, dark green fronds. The fronds are typically between 4 and 10 inches long and have a glossy, leathery texture. It is a hardy and easy-to-grow fern that is suitable for rock gardens and coastal gardens.


Sea Spleenwort, also known as Asplenium marinum, is a fern species found along rocky shorelines in temperate regions around the world. With its unique appearance and hardy nature, this plant has become a popular subject for botanists and nature enthusiasts alike.

Physical Characteristics Sea Spleenwort is a small, evergreen fern that typically grows to a height of 20-30 cm. The fronds of this fern are narrow, linear and tapered with a bright green color. Unlike many other fern species, Sea Spleenwort does not have distinct leaflets. Instead, the fronds are undivided, giving the plant a smooth, unbroken appearance.

Habitat and Distribution Sea Spleenwort is native to coastal regions in Europe, North America, and parts of Asia. It grows in rocky, often vertical habitats such as cliffs, sea walls, and rocky outcrops. This plant is particularly well-adapted to survive in harsh coastal conditions, with the ability to tolerate exposure to salt spray and strong winds.

Ecological Importance Sea Spleenwort plays an important ecological role in its coastal habitats. It helps to prevent soil erosion by anchoring its roots to the rocky substrate and slowing the flow of water. The fronds of this fern also provide shelter for small invertebrates and nesting sites for birds, making it an important part of the local ecosystem.

Cultural Significance Sea Spleenwort has been valued for its medicinal properties by humans for centuries. In traditional Chinese medicine, the plant has been used to treat coughs, asthma, and other respiratory ailments. In Europe, it was believed that Sea Spleenwort could be used to cure spleen disorders, hence the name "Spleenwort".

Growing Sea Spleenwort If you're interested in growing Sea Spleenwort, it can be a challenging plant to cultivate. It requires a rocky, well-drained soil with plenty of moisture and high humidity. In order to create the ideal environment, it is best to plant Sea Spleenwort in a shaded rock garden or on a rock wall where it can receive partial sun.

Sea Spleenwort is a fascinating and unique plant with a rich history of ecological and cultural significance. Its hardy nature and distinctive appearance make it a favorite of botanists and nature enthusiasts alike. Whether you're exploring rocky coastal habitats or looking to add an interesting plant to your garden, Sea Spleenwort is certainly worth a closer look.

One of the interesting features of Sea Spleenwort is its ability to adapt to its harsh coastal environment. The fronds of the plant have a waxy coating that helps to protect them from salt spray and water loss, while the roots are well-suited for anchoring the plant to rocky surfaces. These adaptations allow Sea Spleenwort to thrive in environments that would be too challenging for many other plant species.

Another interesting aspect of Sea Spleenwort is its ability to reproduce both sexually and asexually. The plant produces spores, which are dispersed by the wind, and can also reproduce through vegetative propagation. This means that a single Sea Spleenwort plant can give rise to a colony of plants in the right conditions.

Sea Spleenwort is also a popular subject for scientific research. Scientists have studied the plant's ability to tolerate salt and drought stress, as well as its potential for use in ecological restoration projects. Some researchers are also investigating the potential use of Sea Spleenwort extracts in the development of new medicines.

It's worth noting that Sea Spleenwort is not the only species of Asplenium that can be found in coastal habitats. Other related species, such as A. scolopendrium and A. adiantum-nigrum, can also be found growing in rocky coastal environments in different parts of the world. These plants share many of the same adaptations and ecological roles as Sea Spleenwort, making them all interesting subjects for further study.

One of the interesting uses of Sea Spleenwort in modern times is in the cultivation of "living walls" or green walls. These walls are vertical structures that are covered in living plants, and they are becoming increasingly popular in urban environments where space is limited. Sea Spleenwort, with its ability to grow in rocky environments, is a great candidate for these living walls, as it can thrive in small pockets of soil and rock.

Sea Spleenwort is also a popular plant among fern enthusiasts and collectors. Its unique appearance and hardiness make it a favorite among those who enjoy cultivating and studying ferns. In fact, Sea Spleenwort has been awarded the prestigious Royal Horticultural Society's Award of Garden Merit for its ornamental value.

It's important to note that, while Sea Spleenwort is an interesting and valuable plant, it is also a threatened species in some areas due to habitat loss and human disturbance. It's important to practice responsible and sustainable collecting and cultivation practices to ensure that this plant remains a part of our coastal ecosystems for years to come.

In conclusion, Sea Spleenwort is a fascinating and valuable plant with a rich history of ecological and cultural significance. Its unique adaptations and hardiness make it a valuable subject for scientific research, while its ornamental value and use in green walls make it a popular plant among fern enthusiasts and collectors. As we continue to learn more about this remarkable plant, we can gain a greater appreciation for its role in our coastal ecosystems and its potential for use in a variety of applications.

Distribution Map

Reproduced by kind permission of the BSBI.

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