Medicinal use of St. John's Wort: 

St. John's wort has a long history of herbal use. It fell out of favor in the nineteenth century but recent research has brought it back to prominence as an extremely valuable remedy for nervous problems.
The herb is used in treating a wide range of disorders, including pulmonary complaints, bladder problems, diarrhoea and nervous depression. It is also very effectual in treating overnight incontinence of urine in children.

A tea or tincture of the fresh flowers is a popular treatment for external ulcers, burns, wounds, sores, bruises, cramps etc. An infusion of the flowers in olive oil is applied externally to wounds, sores, ulcers, swellings, rheumatism etc. It is also valued in the treatment of sunburn and as a cosmetic preparation to the skin.

Habitat of the herb: 

Open woods, hedgebanks and grassland, in dry sunny places, usually on calcareous soils.

Edible parts of St. John's Wort: 

The herb and the fruit are sometimes used as a tea substitute. The flowers can be used in making mead.

Other uses of the herb: 

Yellow, gold and brown dyes are obtained from the flowers and leaves. A red is obtained from the flowers after acidification. A red dye is obtained from the whole plant when infused in oil or alcohol. A yellow is obtained when it is infused in water. The plant is said to contain good quantities of tannin, though exact figures are not available.

Propagation of St. John's Wort: 

Seed - sow in a greenhouse as soon as it is ripe in the autumn or in the spring. It normally germinates in 1 - 3 months at 10C. Prick out the seedlings into individual pots when they are large enough to handle and plant them out into their permanent positions in the summer. Division in spring or autumn. Very easy, larger clumps can be replanted direct into their permanent positions, though it is best to pot up smaller clumps and grow them on in a cold frame until they are rooting well. Plant them out in the spring.