How to Grow Hypericum
Hypericum calycinum
Hypericum (St John's Wort) is one of the toughest garden shrubs, thriving in sun or deep shade, poor soil, and dry conditions. It produces cheerful bright yellow flowers over a long summer season. H. calycinum is a vigorous ground-cover species ideal for banks and difficult areas but can be invasive — contain it in small gardens. H. 'Hidcote' is a neater shrub reaching about 1.2m. Cut back hard in early spring for the best flowering. Semi-evergreen, it provides year-round cover in mild areas. Extremely low-maintenance once established.
Yearly Lifecycle
Care Essentials
Rarely needed. Hypericum thrives in poor soil. A spring mulch of compost is beneficial but not essential.
Watch For
- Hypericum rust
- Hypericum beetle
- Aphids
- Invasive spreading (H. calycinum)
Companions
Cotoneaster, Vinca, Geranium (hardy), Euonymus
Track your Hypericum care schedule — pruning, feeding, and seasonal tasks
Start planning freeCare Requirements
☀️ Light
Sun to deep shade; flowers in both
One of the few flowering shrubs that performs well in deep shade. Also thrives in full sun. Extremely adaptable to any light condition.
💧 Watering
Very drought-tolerant once established
Remarkably drought-tolerant once established. Thrives in dry shade under trees where little else will grow. Water newly planted specimens during dry spells in the first year.
🌱 Fertilizing
Rarely needed; thrives in poor soil
Hypericum naturally thrives in poor soil and rarely needs feeding. A spring mulch of compost is beneficial but not essential.
✂️ Pruning
Cut back hard in early spring
Cut all growth back hard in March. H. calycinum can be strimmed to ground level. Taller types cut to a low framework. This produces the best flowering on vigorous new growth.
Growing Tips
Contain H. calycinum
H. calycinum spreads vigorously by underground runners. In small gardens, install a root barrier or grow in a contained area. It is excellent for covering banks and difficult ground where nothing else will grow.
Cut back hard in spring
Cut all growth back hard in March for the best flowering. H. calycinum can be strimmed to ground level. Taller types like 'Hidcote' should be cut to a low framework of 15-30 cm.
Thrives in shade
Unlike most flowering shrubs, hypericum flowers well even in deep shade. This makes it invaluable for difficult shady spots under trees or on north-facing banks.
Pests & Diseases
Pest Hypericum Beetle
Identification: Small metallic green-blue beetles (4-5mm) and dark larvae skeletonising leaves; plants can be severely defoliated
- Pick off beetles and larvae by hand
- Cut back hard — fresh regrowth is usually clean
- Spray with pyrethrin-based contact insecticide if defoliation is severe
Pest Aphids
Identification: Clusters of green aphids on shoot tips; sticky honeydew
- Encourage natural predators
- Blast off with water
- Spray with fatty acid insecticide if severe
Disease Hypericum Rust Melampsora hypericorum
Symptoms: Orange-brown pustules on leaf undersides; leaves yellow and drop prematurely; can cause severe defoliation
Treatment: Remove and destroy affected leaves; cut back hard in spring to remove infected growth
Prevention: Ensure good air circulation; avoid overhead watering; choose resistant varieties
Disease Honey Fungus Armillaria mellea
Symptoms: Sudden wilting and death; white fungal mycelium under bark at the base; honey-coloured toadstools in autumn
Treatment: Remove and destroy affected plants including roots
Prevention: Maintain plant vigour; avoid waterlogged soil
Log Hypericum in your garden — track growth, care, and harvests year after year
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