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Square-stalked St. John's Wort

Hypericum tetrapterum

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Plant Profile

Flowering Months:
Hypericaceae (St. John's Wort)
Life Cycle:
Maximum Size:
60 centimetres tall
Ditches, gardens, marshes, meadows, ponds, riverbanks, waterside, wetland, woodland.

Yellow, 5 petals
The vibrant yellow flowers of Square-stalked St. John's-wort, indigenous to the United Kingdom, possess a charming elegance. Each blossom, measuring approximately 1-2 centimetres in diameter, features five delicate petals that gracefully unfurl during the summer months, adorning meadows, marshes, and stream banks with their cheerful presence. These petals attract pollinators such as bees and butterflies, forming a striking contrast against the backdrop of its opposite, oblong leaves, which bear translucent dots when held to the light. The flowers' radiant hues and symmetrical structure make them a captivating sight in the British countryside during their bloom, which typically occurs from June to September, coinciding with the traditional feast day of St. John the Baptist.
The fruit of Square-stalked St. John's-wort, native to the United Kingdom, is characterized by small, round capsules that develop after the flowering season. These capsules, about 5-7 millimeters in diameter, exhibit a remarkable transformation from green to brown as they mature, containing numerous tiny seeds within. When fully ripe, they split open, releasing the seeds to the wind for dispersal. These fruit capsules are inconspicuous but play a vital role in the plant's reproductive cycle, ensuring the propagation of this fascinating species in the British landscape.
The leaves of Square-stalked St. John's-wort, indigenous to the United Kingdom, are characterized by their oblong shape and distinct appearance. These leaves, typically measuring several centimetres in length, are arranged in pairs along the square stems of the plant. When held up to the light, they reveal translucent dots or glands, a unique feature of this species. The leaves are a lustrous green colour and exhibit a smooth, waxy texture, contributing to their resilience and ability to thrive in a variety of environments, including meadows, marshes, and stream banks. Square-stalked St. John's-wort leaves play a significant role in photosynthesis and are an essential component of this plant's overall aesthetic charm in the British countryside.
Square-stalked St. John's-wort, found in the United Kingdom, is not particularly renowned for its fragrance, as it is primarily appreciated for its visual appeal and potential medicinal properties. The plant's bright yellow flowers, although visually striking, generally do not emit a strong or distinctive scent. Instead, the charm of Square-stalked St. John's-wort lies in its visual aesthetics and ecological significance rather than its olfactory qualities, making it a captivating sight in the British countryside during the summer months, especially for its colourful blooms and potential benefits in herbal medicine.
Other Names:
Four-winged St John's Wort, Peterwort, Square St John's Wort, Square-stemmed St John's Wort, St Peter's Wort.
Frequency (UK):
Occasionally seen  

Other Information


Hypericum tetrapterum, also known as Four-winged St. John's wort, is a perennial herb that is native to Europe and Asia. It has small, yellow flowers that bloom in the summer and is known for its four-winged stems. The plant is often used in garden and landscape design, and is valued for its attractive foliage and showy flowers. It is also known for its medicinal properties and has been used traditionally to treat a variety of ailments.


Hypericum tetrapterum, commonly known as Square-stalked St. John's Wort, is a beautiful and intriguing plant that is native to Europe and parts of Asia. It is a member of the Hypericaceae family, which includes more than 400 species of herbs and shrubs.

One of the most notable features of this plant is its square stem, which is a characteristic of many members of the Hypericaceae family. The stem can reach up to 60 cm in height and is covered in tiny hairs. The leaves of the plant are also covered in tiny hairs, which give them a slightly rough texture. They are oval in shape, with a pointed tip and a slightly wavy edge. The leaves grow in opposite pairs along the stem.

Square-stalked St. John's Wort blooms in the summer months, producing beautiful yellow flowers that are approximately 2 cm in diameter. The flowers have five petals and a cluster of yellow stamens in the center. They are arranged in loose clusters at the top of the stem, and each cluster can contain up to 20 flowers. The plant is a popular choice for gardeners who want to add a splash of yellow to their outdoor spaces.

In addition to its ornamental value, Square-stalked St. John's Wort has a long history of medicinal use. It contains a number of compounds that are believed to have therapeutic properties, including hypericin and hyperforin. These compounds are thought to have antidepressant, antiviral, and antibacterial properties, and are often used to treat conditions such as depression, anxiety, and nerve pain.

Despite its many benefits, Square-stalked St. John's Wort should be used with caution. It can interact with a number of medications, including antidepressants, birth control pills, and blood thinners. It can also cause sensitivity to sunlight, so it is important to wear sunscreen or protective clothing when using products containing St. John's Wort.

Square-stalked St. John's Wort is a fascinating and beautiful plant that has been valued for its medicinal properties for centuries. Whether you are a gardener looking to add some yellow to your outdoor space or someone who is interested in natural remedies, this plant is definitely worth considering. Just be sure to use it with caution and talk to your doctor before using it in combination with any medications.

Square-stalked St. John's Wort has a wide range of habitats, from woodlands to meadows, and it is commonly found in Europe and parts of Asia. It prefers well-drained soil and is tolerant of both sun and shade. It is also quite hardy, withstanding temperatures as low as -20°C.

The plant has been used for medicinal purposes for centuries, and there is evidence that it was used by the ancient Greeks and Romans. The name "St. John's Wort" comes from the fact that the plant was traditionally harvested on St. John's Day, which falls on June 24th. The plant was believed to have protective properties and was often hung in doorways or carried as a talisman to ward off evil spirits.

In addition to its medicinal uses, Square-stalked St. John's Wort has a number of other traditional uses. The plant was often used to make dyes, and the flowers were used to create a yellow dye that was used to color wool and other fabrics. The plant was also used to make a tea that was said to have a calming effect.

In recent years, Square-stalked St. John's Wort has become increasingly popular as a natural remedy for depression and anxiety. A number of clinical studies have shown that the plant can be effective in treating mild to moderate depression. However, it is important to note that St. John's Wort should not be used as a substitute for conventional medical treatment, and anyone suffering from depression should talk to their doctor before using the plant as a treatment.

Square-stalked St. John's Wort is a fascinating and versatile plant that has a long and rich history. Whether you are interested in gardening, natural remedies, or traditional crafts, this plant is definitely worth learning more about. Just be sure to use it with caution and talk to your doctor before using it in combination with any medications.

Aside from its traditional uses in medicine and crafting, Square-stalked St. John's Wort has also been studied for its potential benefits in skincare. The plant contains a number of compounds, including hypericin and hyperforin, that are believed to have antibacterial and anti-inflammatory properties. As a result, St. John's Wort extract has been added to a variety of skincare products, including creams, lotions, and serums.

In addition, St. John's Wort oil is often used topically to soothe burns, cuts, and other skin irritations. The oil is made by infusing St. John's Wort flowers in a carrier oil, such as olive oil or almond oil. The resulting oil is rich in antioxidants and anti-inflammatory compounds and is believed to help speed up the healing process.

Despite its many potential benefits, it is important to use St. John's Wort with caution, as it can interact with a number of medications and may cause side effects in some individuals. In addition, the plant can be toxic in high doses, so it is important to follow dosage recommendations carefully.

In conclusion, Square-stalked St. John's Wort is a versatile and fascinating plant with a long history of traditional use in medicine, crafting, and skincare. Whether you are interested in gardening, natural remedies, or skincare, this plant is definitely worth exploring further. Just be sure to use it with caution and talk to your doctor before using it in combination with any medications.

30 Fascinating Facts About Square-stalked St. John's Wort

Here are 30 facts about Square-stalked St. John's-wort (Hypericum tetrapterum):

  1. Square-stalked St. John's-wort is a perennial herbaceous plant.

  2. It belongs to the Hypericum genus and is part of the Hypericaceae family.

  3. This plant is native to Europe and can be found in various parts of the continent.

  4. Square-stalked St. John's-wort typically grows in damp or wet habitats like marshes, meadows, and along streams.

  5. The scientific name, Hypericum tetrapterum, refers to the four-winged stem characteristic of this species.

  6. It is known by various common names, including square-stalked St. John's-wort, square-stemmed St. John's-wort, and four-wing St. John's-wort.

  7. The plant can reach heights of up to 90 centimeters (35 inches).

  8. Square-stalked St. John's-wort produces bright yellow flowers with five petals, typically measuring 1-2 centimeters in diameter.

  9. The flowers bloom during the summer months, usually from June to August.

  10. This plant is attractive to pollinators like bees and butterflies.

  11. The leaves of Square-stalked St. John's-wort are opposite and oblong, with translucent dots visible when held to the light.

  12. It has been used historically in herbal medicine for its potential healing properties.

  13. Some people believe it has mild sedative and anti-inflammatory properties.

  14. Square-stalked St. John's-wort is not to be confused with the more well-known Common St. John's-wort (Hypericum perforatum), which is often used for its mood-enhancing properties.

  15. The plant's name "St. John's-wort" is derived from its traditional flowering around the feast day of St. John the Baptist, which falls on June 24th.

  16. Square-stalked St. John's-wort is a perennial, which means it lives for multiple years.

  17. It reproduces both by seeds and vegetatively through rhizomes.

  18. The plant's square stem is one of its distinctive features, giving it its common name.

  19. Square-stalked St. John's-wort can tolerate some shading but thrives in full sunlight.

  20. In some regions, it is considered an invasive species because of its ability to spread rapidly.

  21. The roots of Square-stalked St. John's-wort can extend deep into the soil.

  22. It is known to be resistant to grazing by livestock due to its bitter taste.

  23. The plant has been studied for its potential as a natural dye source for textiles.

  24. Square-stalked St. John's-wort may have traditional folklore associated with warding off evil spirits.

  25. This plant has no known toxic properties but is not commonly used for culinary purposes.

  26. It has a relatively short blooming period, with flowers lasting only a few weeks.

  27. Square-stalked St. John's-wort is a hardy species that can withstand various weather conditions.

  28. In traditional herbal medicine, it was used externally for its potential wound-healing properties.

  29. The oil extracted from the plant has been used in traditional skin care remedies.

  30. In some areas, Square-stalked St. John's-wort is considered a threatened or protected species due to habitat loss.


Square-stalked St. John's-wort filmed at Barrow Wake in the Cotswolds on the 25th June 2023.


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Distribution Map

Reproduced by kind permission of the BSBI.

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