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Lake Loosestrife

Lysimachia terrestris

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Plant Profile

Flowering Months:
Lythraceae (Purple Loosestrife)
Life Cycle:
Maximum Size:
1 metre tall
Bogs, gardens, marshes, meadows, riverbanks, waterside, wetland.

Yellow, 5 petals
Clusters of yellow flowers. The petals are pointed and streaked black. Flowers measure about 2cm in diameter.
A dark, dotted fruit capsule.
A perennial flower with lance-shaped leaves, up to 4 inches (10cm) long. The untoothed leaves are covered in tiny dots and in opposite pairs up the stems. Lake Loosestrife can be found growing in Sussex and at Lake Windermere in the Lake District.
Other Names:
Earth Loosestrife, Swamp Candles, Swamp Loosestrife, Terrestrial Loosestrife.
Frequency (UK):
Rarely seen  

Similar Species

Other Information


Lysimachia terrestris, also known as Swamp Candles or Terrestrial Loosestrife, is a species of perennial herb that is native to North America. It is known for its small, yellow, star-shaped flowers that bloom in the summer and its basal leaves. The plant can grow up to 2-3 feet in height. It prefers moist, well-drained soils and full sun to partial shade, and it is often found in wetland habitats and along stream banks. Lysimachia terrestris is often grown as an ornamental plant in gardens and is also used in naturalized settings and wetland restoration projects. It is a hardy plant and is well suited to growing in moist, shady areas, it is also known to be a good plant for stabilization of stream banks and other wetland areas.


Lake Loosestrife, also known as Lysimachia terrestris, is a perennial herbaceous plant that grows in damp habitats such as marshes, wetlands, and the banks of streams and lakes. It is native to North America and can be found in most of the United States, including Alaska and Hawaii, as well as in Canada.

The plant has long, narrow leaves that are arranged in opposite pairs along the stem. The leaves are smooth and have pointed tips, and they can be up to 3 inches long. The flowers of Lake Loosestrife are small and yellow, and they bloom from June to August. The flowers grow in clusters at the top of the stem, and they have five petals that are fused at the base.

One of the most interesting things about Lake Loosestrife is its ability to adapt to different environments. It can grow in full sun or partial shade, and it can tolerate a wide range of soil types, from wet to dry. This adaptability has allowed it to spread rapidly and become invasive in some areas.

Invasive species are a significant problem in many ecosystems around the world, and Lake Loosestrife is no exception. When it invades a wetland, it can outcompete native plants for resources such as sunlight, nutrients, and water. This can lead to a reduction in biodiversity, as well as changes in the physical structure of the wetland. In some cases, the invasion of Lake Loosestrife can even lead to the loss of critical habitat for wildlife.

Despite its invasive tendencies, Lake Loosestrife does have some beneficial uses. The plant has been used in traditional medicine to treat a variety of ailments, including respiratory problems, digestive issues, and skin conditions. It has also been used as a natural dye, and the flowers can be used to add a yellow color to fabrics.

In order to control the spread of Lake Loosestrife, it is important to take measures to prevent its introduction into new areas. This can include cleaning equipment and boats before moving them between bodies of water, as well as avoiding planting the species in gardens or other landscaped areas. If Lake Loosestrife is already established in a wetland, it may be possible to control it through mechanical or chemical means, although this can be difficult and expensive.

Lake Loosestrife is a member of the Primrose family, which includes other plants such as primrose, shooting star, and evening primrose. The plant's Latin name, Lysimachia, is derived from the Greek word "lysimache," which means "loose battle," referring to its ancient use as a herbal remedy for treating wounds suffered in battle.

One interesting aspect of Lake Loosestrife is its ability to reproduce through both seeds and vegetative means. It produces small, black seeds that can remain viable in the soil for several years, and it also spreads through underground rhizomes, which can form new plants. This makes it difficult to control once it becomes established in a wetland.

Despite its invasive tendencies, Lake Loosestrife can be a valuable food source for wildlife. The leaves and stems are eaten by a variety of herbivores, including deer, moose, and muskrats, and the flowers provide nectar for bees, butterflies, and other pollinators. In addition, the plant's dense growth can provide cover and nesting habitat for birds and other small animals.

Efforts to control the spread of Lake Loosestrife are ongoing, and there is ongoing research into more effective and environmentally friendly methods of control. One promising approach is the use of biological controls, such as insects or fungi, that can target the plant without harming other species. This approach is still in the experimental stage, but it holds promise for reducing the negative impacts of invasive species in wetland ecosystems.

Lake Loosestrife has been used for centuries for its medicinal properties. In traditional medicine, it has been used to treat a wide range of conditions, including coughs, diarrhea, and skin irritations. It was also used as an astringent, diuretic, and emetic. Some Native American tribes used Lake Loosestrife to treat snakebites and to promote healing of wounds.

In modern times, the use of Lake Loosestrife as a medicinal plant has declined, partly due to concerns about its potential toxicity. Some of the compounds found in the plant have been shown to have cytotoxic effects, meaning they can damage or kill cells. However, further research is needed to fully understand the potential risks and benefits of using Lake Loosestrife for medicinal purposes.

One potential benefit of Lake Loosestrife is its use as a natural dye. The flowers of the plant contain a yellow pigment that can be extracted and used to color fabrics. In the past, this was a common practice, and Lake Loosestrife was known as one of the "yellow dyes." Today, it is still used by some fiber artists and natural dyers as a source of yellow color.

Another interesting aspect of Lake Loosestrife is its cultural significance. In some Native American traditions, the plant is associated with renewal and rebirth, and it is used in various rituals and ceremonies. For example, the Ojibwe people use the plant in the Midewiwin ceremony, which is a traditional healing ceremony.

In conclusion, Lake Loosestrife is a plant that has played an important role in human culture and medicine for centuries. While it can pose a threat to wetland ecosystems when it becomes invasive, it also has valuable ecological and cultural benefits. By continuing to study and understand this plant, we can work towards more effective management strategies that protect both human communities and natural ecosystems.

Distribution Map

Reproduced by kind permission of the BSBI.

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