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Marsh Pea

Lathyrus palustris

Please keep in mind that it is illegal to uproot a plant without the landowner's consent and care should be taken at all times not to damage wild plants. Wild plants should never be picked for pleasure and some plants are protected by law.
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Plant Profile

Flowering Months:
Fabaceae (Pea)
Also in this family:
Alpine Milk-vetch, Alsike Clover, Birdsfoot, Birdsfoot Clover, Bird's-foot Trefoil, Bithynian Vetch, Bitter Vetch, Black Broom, Black Medick, Bladder Senna, Broad Bean, Broad-leaved Everlasting Pea, Bur Medick, Burrowing Clover, Bush Vetch, Clustered Clover, Common Broom, Common Gorse, Common Laburnum, Common Restharrow, Common Vetch, Crimson Clover, Crown Vetch, Dragon's Teeth, Dwarf Gorse, Dyer's Greenweed, False Acacia, Fine-leaved Vetch, Fodder Vetch, Garden Lupin, Garden Pea, Goat's Rue, Grass Vetchling, Greater Bird's-foot Trefoil, Hairy Bird's-foot Trefoil, Hairy Greenweed, Hairy Tare, Hairy Vetchling, Hairy-fruited Broom, Haresfoot Clover, Hop Trefoil, Horseshoe Vetch, Hungarian Vetch, Kidney Vetch, Knotted Clover, Large Trefoil, Lesser Trefoil, Lucerne, Meadow Vetchling, Narrow-leaved Bird's-foot Trefoil, Narrow-leaved Everlasting Pea, Narrow-leaved Vetch, Nootka Lupin, Norfolk Everlasting Pea, Orange Birdsfoot, Petty Whin, Purple Milk-vetch, Purple Oxytropis, Red Clover, Reversed Clover, Ribbed Melilot, Rough Clover, Russell Lupin, Sainfoin, Scorpion Senna, Scottish Laburnum, Sea Clover, Sea Pea, Sickle Medick, Slender Bird's-foot Trefoil, Slender Tare, Slender Trefoil, Small Melilot, Small Restharrow, Smooth Tare, Spanish Broom, Spanish Gorse, Spiny Restharrow, Spotted Medick, Spring Vetch, Strawberry Clover, Suffocated Clover, Sulphur Clover, Tall Melilot, Toothed Medick, Tree Lupin, Tuberous Pea, Tufted Vetch, Twin-headed Clover, Two-flowered Everlasting Pea, Upright Clover, Upright Vetch, Western Clover, Western Gorse, White Broom, White Clover, White Lupin, White Melilot, Wild Liquorice, Wood Vetch, Yellow Oxytropis, Yellow Vetch, Yellow Vetchling, Zigzag Clover
Life Cycle:
Maximum Size:
120 centimetres tall
Fens, grassland, marshes, meadows, riversides, waterside, wetland.

Purple, 5 petals
Purplish-blue, pea-like flowers, up to 2cm in size. Flowers appear together in short, long-stalked spikes. 2 to 6 flowers per spike. 10 stamens. Pollinated by insects.
Brown, flat, pea-like pods, measuring anything up to 6cm long. 6 to 12 seeds per pod.
The leaves consist of 2 to 3 narrow, oval to oblong pairs of leaflets. A branched tendril is situated at the end of each leaf. Leaf stalks are winged. Sparsely hairy. Perennial.
Other Names:
Slenderstem Peavine, Wild Sweet Pea.
Frequency (UK):

Other Information


Lathyrus palustris, also known as marsh pea or wild sweet pea, is a perennial herb in the family Fabaceae. It is native to Europe and Asia and can be found in wetland habitats such as marshes, fens, and wet meadows. The plant has delicate leaves and small, pink or purple flowers that bloom in the summer. The root of the plant is edible, but it is not commonly consumed, also it's not considered to be toxic. The seeds of Lathyrus palustris are toxic and not to be consumed, eating large amounts of them over a period of time can cause a neurological disorder called lathyrism.


Marsh pea (Lathyrus palustris) is a herbaceous perennial plant that belongs to the family Fabaceae. It is native to North America and can be found in wetlands, swamps, and along the edges of streams and lakes. Marsh pea is also known by several other common names, including wild sweet pea, bog sweet pea, and water vetchling.

Marsh pea can grow up to two meters tall and has a spreading habit. The leaves are alternate and pinnately compound, with 4-8 pairs of leaflets. The flowers are pink-purple and bloom from June to August. The fruit is a linear pod containing several seeds.

Marsh pea is an important plant in wetland ecosystems as it helps to stabilize soil and prevent erosion. It also provides food and habitat for various wildlife species, including waterfowl, beavers, and muskrats. Additionally, Marsh pea has medicinal properties and has been used by indigenous communities to treat a variety of ailments, including colds, coughs, and digestive problems.

Despite its ecological and medicinal importance, Marsh pea can be toxic if consumed in large quantities. The plant contains high levels of the amino acid beta-N-oxalyl-L-alpha,beta-diaminopropionic acid (BOAA), which can cause a neurological disorder called lathyrism in humans and livestock. Lathyrism is characterized by muscle weakness, paralysis, and in severe cases, permanent disability.

Marsh pea is a relatively easy plant to grow in the garden and can be an attractive addition to a wetland or water garden. It prefers moist soil and full sun to partial shade. It can also tolerate periodic flooding and is a good choice for rain gardens.

Marsh pea can be propagated from seed or by dividing established clumps in the spring. It is a long-lived perennial that can provide many years of beauty and ecological benefits in the garden.

In addition to its ecological and medicinal benefits, Marsh pea has also been used in traditional Native American cultures for basket weaving. The fibrous stems of the plant can be harvested and woven into baskets, mats, and other useful items.

There are several other interesting facts about Marsh pea worth mentioning. For example, the plant is pollinated by bees and butterflies, and its seeds are dispersed by water and animals.

Marsh pea is also part of a group of leguminous plants that are able to fix nitrogen from the atmosphere and convert it into a form that is available to other plants. This makes Marsh pea an important contributor to the health and fertility of wetland ecosystems.

In terms of its medicinal uses, Marsh pea has been used by indigenous communities for generations to treat a variety of ailments. For example, the plant has been used as a diuretic, a laxative, and a treatment for rheumatism and arthritis.

In addition to its medicinal properties, Marsh pea has also been used for culinary purposes. The young shoots and leaves can be eaten raw or cooked and have a slightly sweet and nutty flavor. However, it is important to use caution when consuming the plant as it can be toxic in large quantities.

In addition to its ecological, medicinal, and cultural significance, Marsh pea has also been studied for its potential as a bioenergy crop. The plant has a high biomass yield and can grow in wetlands and other marginal lands that are not suitable for other crops.

Furthermore, Marsh pea has been found to be tolerant to various environmental stressors such as drought, salinity, and flooding. This makes it a promising candidate for use in phytoremediation, a process in which plants are used to remove pollutants from contaminated soil or water.

Studies have also shown that Marsh pea may have potential in the development of natural pesticides. Extracts from the plant have been found to have insecticidal and fungicidal properties, making it a potential alternative to synthetic pesticides that can have negative impacts on the environment and human health.

Another interesting aspect of Marsh pea is its historical and cultural significance. The plant has been used by various indigenous communities in North America for thousands of years for its medicinal, culinary, and cultural properties.

For example, the Dakota and Lakota tribes used Marsh pea to treat snake bites and to make a tea for colds and coughs. The plant was also used in basket weaving and as a source of dye for textiles.

Similarly, the Ojibwe tribe used Marsh pea to treat a variety of ailments, including sore throats, stomach pains, and fevers. They also used the plant as a diuretic and as a poultice for wounds and injuries.

Today, Marsh pea continues to be an important plant for many indigenous communities, and efforts are underway to preserve and promote its use for future generations.

Overall, Marsh pea is a plant with a rich history and many ecological, medicinal, cultural, and potential economic benefits. Its importance to various communities throughout history and its potential for future use make it a plant worth studying and preserving.

Distribution Map

Reproduced by kind permission of the BSBI.

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