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How to grow St. John's wort

How to grow St John’s wort

All you need to know about growing St. John's wort, in our detailed Grow Guide.

A table displaying which months are best to sow, plant and harvest.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Plant
Plant

Do not Plant in January

Do not Plant in February

Do not Plant in March

Do not Plant in April

Do Plant in May

Do Plant in June

Do Plant in July

Do Plant in August

Do Plant in September

Do not Plant in October

Do not Plant in November

Do not Plant in December

Flowers
Flowers

Plant does not flower in January

Plant does not flower in February

Plant does not flower in March

Plant does not flower in April

Plant does not flower in May

Plant does not flower in June

Plant does flower in July

Plant does flower in August

Plant does flower in September

Plant does flower in October

Plant does not flower in November

Plant does not flower in December

Fruits
Fruits

Plant does not fruit in January

Plant does not fruit in February

Plant does not fruit in March

Plant does not fruit in April

Plant does not fruit in May

Plant does not fruit in June

Plant does not fruit in July

Plant does not fruit in August

Plant does fruit in September

Plant does fruit in October

Plant does fruit in November

Plant does not fruit in December

Cut back
Cut back

Do not Cut back in January

Do not Cut back in February

Do Cut back in March

Do Cut back in April

Do Cut back in May

Do not Cut back in June

Do not Cut back in July

Do not Cut back in August

Do not Cut back in September

Do not Cut back in October

Do not Cut back in November

Do not Cut back in December

  • Plant size

    1m height

    50cm spread

St. John’s wort (Hypericum spp.) refers to a genus of annuals, perennials and shrubs, typically with bright yellow, open flowers with prominent stamens. Some species develop red-brown autumn berries. Named after the feast day of St John the Baptist, around which many European species flower, the most well-known of the genus is the perforated St. John’s wort (Hypericum perforartum), which is native to Britain and Northern Europe, and much of Asia. Traditionally, Hypericum perforartum has been used as an herb to treat depression, however all plants in the genus are mildly poisonous to people and animals, and in large doses can cause sensitivity to light (leading to dermatitis). If considerable quantities are eaten they could even cause death.

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While most garden varieties of St. John’s wort are compact growing and easy to manage, Hypericum perforartum spreads by creeping rhizomes and seeds. It has been introduced in many parts of the world and is considered an invasive species in parts of Australia, South Africa, and the Americas. In some regions, including the United States, Hypericum perforartum is known as klamath weed. However, there are plenty of varieties to grow, including some which do well in pots.

How to grow St. John’s wort

Grow St. John’s wort in moist but well-drained soil in full sun to partial shade. Shrubby hypericums, such as Hypericum ‘Hidcote’ can become untidy and should be pruned in spring. If they’ve out-grown their space they can be cut back hard if necessary.


Where to grow St John’s wort

Hypericum growing with rudbeckia in a pot

Hypericum perforartum is perfect for growing in a wildflower meadow or other wild planting scheme. Shrubby types, including Hypericum ‘Hidcote’, are ideal for ornamental borders, while low-growing St John’s wort are best used as ground cover. Some species, including Hypericum inodoriumcan be grown in pots.


How to plant St. John’s wort

Plant St. John’s wort as you would any plant – dig a hole slightly wider but no deeper than the original pot, tease any restricted roots out from the base of the rootball and place it into the hole before backfilling with soil. Firm around the rootball gently with your foot and water well.


St John’s wort care

All St John’s worts are easy to grow and tolerant of a wider range of conditions, including temporary flooding. However, during prolonged periods of drought they will benefit from supplementary watering, particularly young plants. Many shrubby varieties can look untidy over the year and should be cut back in spring. If they’ve out-grown their space they can be cut back hard.


How to propagate St. John’s wort

St John’s wort berries

Hypericum perforartum is a prolific self-seeder so you may find you are removing seedlings rather than actively trying to propagate from it. Larger, shrubby types can be propagated from hardwood cuttings.


Growing St. John’s wort: pests and diseases

St John’s wort is not troubled by pests or diseases.


Advice on buying St. John’s wort

  • Ensure you’re buying the right St. John’s wort for your garden – there are many types, from low-growing ground-cover hypericums to larger shrubs
  • Some varieties may be available at garden centres but you’ll find more choice online
  • Always check plants for signs of damage before planting

Where to buy St. John’s wort

Types of St John’s wort to grow

Hypericum × hidcoteense ‘Hidcote’ – one of the most popular St. John’s wort, bearing masses of yellow blooms followed by red-brown berries. Grow in sun to partial shade. Height x Spread: 1.2m x 1.5m

Hypericum × moserianum ‘Tricolor’ – a low-growing variety, perfect for using as ground cover. Needs protection from cold winds. Semi-evergreen. Grow in sun to partial shade. H x S: 30cm x 60cm

Hypericum inodorium ‘Magical white’ – Bears masses of yellow flowers, followed by white fruits. Often used in flower arranging and perfect for growing in pots or as ground cover. Grow in sun to partial shade.  H x S: 50cm x 80cm

Hypericum elodes – marsh hypericum is suitable for moist soils and is perfect for edging ponds. As a herbacesou perennial, it dies down in autumn and grows again in spring. Grow in sun to partial shade. H x S: 30cm x 1m

Hypericum x dummeri ‘Peter Dummer’ – a low-growing, rounded shrub with yellow flowers and orange stamens, red-tinted fruit and lovely autumn colour. Semi-evergreen. Grow in sun to shade. H x S: 30cm x 1m

Hypericum ‘Magical Red Flame’ – compact shrub perfect for the front of a border. Bears flowers and fruit at the same time. Grow in sun to shade.  H x S: 1m x 1m

Hypericum ‘Gemo’ – low-growing shrub with semi-evergreen foliage. Large yellow flowers with golden stamens are followed by red-blushed fruits. Grow in sun to shade. H x S: 90cm x 90cm

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