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Hairy St. John's Wort

Hypericum hirsutum

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Plant Profile

Flowering Months:
Hypericaceae (St. John's Wort)
Life Cycle:
Maximum Size:
150 centimetres tall
Grassland, meadows, riverbanks, roadsides, scrub, wetland, woodland.

Yellow, 5 petals
Pale yellow flowers with black dots on the edge of the sepals. Sometimes red-veined. Approximately 2cm in diameter.
A 3-parted capsule.
The only common British species of St. John's Wort that has downy leaves and stems. The stems are round with no ridges. On close inspection, translucent dots are present on the leaves. The leaves are yellowish green and without black dots around the edges (as is present with some species of St. John's Wort).
Frequency (UK):
Occasionally seen  

Other Information


Hypericum hirsutum, also known as Hairy St. John's wort or hairy hypericum, is a perennial herb that is native to North America. It has small, yellow flowers that bloom in the summer and is known for its hairy leaves and stems. The plant is often found in wetland, meadows, and woodlands, 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.


Hairy St. John's Wort, also known by its scientific name Hypericum hirsutum, is a herbaceous perennial plant that is native to Europe and western Asia. It belongs to the family Hypericaceae, which includes over 400 species of plants. The plant is named after St. John the Baptist, as it flowers around the time of his feast day.

The hairy St. John's Wort plant grows up to 1.5 meters in height and has a shrubby habit, with multiple branches that are covered in small, dark green leaves. The leaves are oval-shaped and have a hairy texture on the underside, which gives the plant its name. The plant produces clusters of yellow flowers that bloom from June to September. The flowers have five petals and numerous stamens that give them a distinctive appearance.

One of the most interesting aspects of the hairy St. John's Wort plant is its medicinal properties. The plant has been used in traditional medicine for centuries to treat a variety of ailments, including anxiety, depression, and insomnia. It is believed that the plant contains hypericin and hyperforin, which are compounds that have been shown to have antidepressant properties. These compounds work by inhibiting the reuptake of serotonin, a neurotransmitter that is associated with mood regulation.

In addition to its antidepressant properties, hairy St. John's Wort has also been used to treat wounds and skin conditions. The plant contains tannins, which have astringent properties that can help to tighten and dry out the skin. It is also believed to have antibacterial and antiviral properties, which make it useful for treating infections.

Despite its many benefits, it is important to note that hairy St. John's Wort can have some side effects. The plant has been known to interact with certain medications, including antidepressants and birth control pills. It can also cause photosensitivity, which means that it can make the skin more sensitive to sunlight. This can lead to sunburn and other skin irritations. For these reasons, it is important to consult with a healthcare provider before using hairy St. John's Wort as a treatment for any condition.

Hairy St. John's Wort is a fascinating plant that has a long history of use in traditional medicine. It is known for its antidepressant, wound-healing, and antibacterial properties, among others. While it can have some side effects, it remains a valuable tool in the treatment of various conditions. As with any medicinal plant, it is important to use it safely and under the guidance of a healthcare professional.

The hairy St. John's Wort plant is easy to grow and can be a great addition to a medicinal herb garden. It prefers well-drained soil and full sun, but can tolerate partial shade. It can be propagated through seeds, cuttings, or by dividing the root ball of an established plant.

In addition to its medicinal properties, hairy St. John's Wort has also been used for other purposes. The plant was traditionally burned as a form of incense to ward off evil spirits and provide protection against negative energy. It has also been used as a natural dye, producing a yellow color that was used to color fabrics.

Hairy St. John's Wort is also an important plant for wildlife. The flowers provide nectar for bees, butterflies, and other pollinators, while the leaves and stems are a source of food for caterpillars. The plant also provides habitat and cover for small mammals and birds.

Unfortunately, like many other wild plant species, hairy St. John's Wort is threatened by habitat loss and overcollection. In some areas, the plant is classified as a rare or endangered species. As such, it is important to be mindful of where and how you harvest the plant, and to only do so sustainably.

The hairy St. John's Wort plant is a valuable and fascinating species that has a long history of use in traditional medicine and beyond. While it is important to use the plant safely and under the guidance of a healthcare professional, it remains an important tool for treating various conditions. Its ecological importance and cultural significance make it a plant worth protecting and conserving for future generations.

In addition to its traditional uses, recent scientific research has investigated the potential of hairy St. John's Wort for the treatment of various health conditions. Studies have shown that it may have anti-inflammatory and antioxidant properties, making it a potential treatment for conditions such as arthritis and other inflammatory disorders. It may also have potential for the treatment of certain types of cancer, as some studies have shown that it may have cytotoxic effects on cancer cells.

Furthermore, the plant has been shown to have analgesic properties, making it a potential treatment for pain management. Studies have also investigated its potential use for the treatment of neurological disorders, such as Alzheimer's disease and Parkinson's disease. While more research is needed to confirm these potential benefits, the results so far are promising.

Overall, hairy St. John's Wort is a plant that has been used for centuries for its medicinal properties and other uses. While it is important to use the plant safely and under the guidance of a healthcare professional, it has potential as a treatment for a variety of health conditions. Its cultural and ecological importance also make it a plant worth conserving and protecting.


Hairy St. John's Wort filmed at Lower Moor Nature Reserve in Wiltshire on the 28th June 2023.


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