Easily grown in any reasonably good well-drained but moisture retentive soil. Succeeds in dry soils. Plants grow well in sun or semi-shade but they flower better when in a sunny position. St. John's wort is often found as a weed in the garden. It grows well in the summer meadow and is a useful plant for attracting insects. The whole plant, especially when in bloom, gives off a most unpleasant smell when handled. Hypericum perforatum is apparently an allotetraploid that would appear to have arisen from a cross between two diploid taxa, viz. H. maculatum subsp. maculatum (Europe to western Siberia) and H. attenuatum (western Siberia to China).

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

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 10°c. 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.

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