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Pruning guide · Herb
St John’s wort: when and how to prune
Hypericum perforatum
St John’s wort is best pruned in March and September.
| Pruning months | March and September |
|---|---|
| Flowering | June–August |
| Good for bees, butterflies and birds | Yes, for bees |
| Native to Belgium | Yes |
| Poisonous to people and pets | Yes, take care with children and pets |
St John’s wort: when to prune it?
Real pruning is not needed. After flowering, in September, cut back the spent stems; in March, remove last year’s dead stems.
St John’s wort: how to prune it?
- In September, cut spent stems back to a few centimetres above the ground if you want to prevent seedlings.
- If you leave them, it self-seeds and insects shelter in them over winter.
- In March, remove the dead stems before the new shoots appear.
- Chop off runners that spread too far at the edge with a spade.
How much to cut, and how often?
- There are 2 pruning periods a year: March and September. You don’t have to prune in every one.
What does it mean for wildlife?
- St John’s wort flowers in June–August, when it attracts bees.
- As a native plant, it feeds more insects than a non-native species.
Caution: Wear gloves when cutting back: the sap can make the skin more sensitive to sunlight. St John’s wort is poisonous: wear gloves and keep clippings away from children, pets and livestock.
Nearby: related pruning guides
- Gold flower (Hypericum × moserianum)
- Rose of Sharon (Hypericum calycinum)
- Tall tutsan (Hypericum × inodorum)
- Tutsan
Plant profile: St John’s wort · Pruning calendar and basic rules
This guide is compiled from the Bladwijzer plant profile and pruning calendar.