Well known in recent times for its medicinal use in the treatment of depression, this versatile plant has more traditionally been used as a topical antiseptic and anti inflammatory wound healer. You can use it as an oil or turn it into a soothing balm.easily grown and adding a splash of yellow to summer borders, st john's wort produces a profusion of flowers which when harvested, bruised and left to steep in sunflower oil on a sunny windowsill, magically turns the oil from yellow to bright red, by which time it is ready to do its stuff next time you get into a scrape!flowers late may june. Height 70 80cm 27 31 spread 40 50cm 16 20.view the recipe forst john’s wort healing balm traditionally valued for its antiseptic and anti inflammatory wound healing properties.