St John’s Wort (Hypericum Perforatum) is a biennial yellow-flowering plant with medicinal properties, which has been used by various cultures since the Ancient Greeks, to treat ailments varying from respiratory disease to depression. Popular with some gardeners due to its cheerful sunshine colours, it is also considered a noxious weed in many countries.
St John’s Wort originated in Europe but through colonial expansion it was introduced to the Americas, Africa, Australia and parts of Asia. It grows quickly and expands rapidly and is capable of strangling vibrant ecosystems when introduced to new land. When eaten by livestock it can cause photosensitivity, spontaneous abortion and even death.
Due to its prolific nature and the danger it poses to cattle farmers in countries such as New Zealand and South Africa, they are actively encouraged to exterminate it on sight.
However, it is also considered by many to be a medicinal herb and even had spiritual significance for some cultures. The Greeks believed that it warded off evil spirits – its scientific name hypericum perforatum derives from the greek meaning ‘over an apparition’. Native Indians have used tea made from the herb to cure tuberculosis.
In the modern era it is considered a cure for depression, particularly in Germany. Recent studies have shown that it may be as effective as Prozac as a treatment for depression, though it appears to be ineffectual in treating related problems such as stress and anxiety.
The success in treating depression is thought to result from high concentrations of the chemical hyperflorin found in the plant. Hyperflorin is thought to increase levels of serotonin in the brain and promote a positive mood.
Scientists are still unsure however of the exact mechanism for this and further studies are ongoing. There have also been attempts to adapt extracts of the plant for treatment of other illnesses, such Parkinson’s and ADHD.
As well as being medicinal, the bright and vibrant colours of the herbs flowers also make it popular in some gardens. It is very easy to grow and will take to almost any flower bed, including poor soils and shady areas.
The preference is for moist and light soils but it will still grow in sandy, coarser beds. It is hardy and needs little attention once given a start – though care must be taken to ensure it does not begin to encroach on other plants.
St John’s Wort is a prolific weed that is vilified by most land cultivators but which has real and important medicinal qualities and can be used as a substitute for many antidepressant drugs, without so many side effects.