Great St. John’s Wort

Botanical Name: Hypericum pyramidatum

En français: Millepertuis

Magnificent vivacious plant with flowers that can be up to 5cm wide. Easy to cultivate, prefers damp and full sun. It can grow very tall with the rich soil conditions.

The top of the upper stems will terminate/branch into 1-5 short stems, each with a single .

Used in borders, woodland margins or slopes.

St. John’s wort is most commonly used for depression and symptoms such as anxiety, tiredness, loss of appetite and trouble sleeping. There is strong evidence that it is effective for mild to moderate depression.

It has been known to help with inflammation due to pro-inflammatory genes.



Width: 1 to 3 feet

Water: Medium water required


Native to Eastern Canada

Best Soil: Sandy Loam / Loam / Clay- Moisture Well drained, medium to moist

Bumblebees are a primary pollinator of this plant. Some moths and butterflies frequent the plant. You should not have any trouble growing this flower if you plant in recommeded conditions.

Its natural habitat: St John’s Wort can be found in forests, meadows, banks of rivers and streams, moist thickets.

Great St John’s Wort has a beautiful yellow flower that blooms for about 3 weeks in June-July-August.

Propagating Hypericum pyramidatum

St John’s Wort prefers well-drained soils in full or partial sun. You may have some unwanted seedlings sprout up from seeds or roots. Those can be pulled or roots cut if needed. It isn’t aggressive if other competition is present. Due to its height, it is best planted at the back of gardens to avoid crowding and shading.

Caring for Great St. John’s Wort

Easily grown in moist, well-drained soils in full sun to part shade.

Cut off seed heads to prevent spread. Pull unwanted volunteers in Spring.

Companion plant suggestions include Try pairing Hypericum prolificum with Aster oblongifolius, Hibiscus moscheutos, Monarda fistulosa.

Pruning Millepertuis

The St. John’s wort needs pruning every year to keep it looking nice and full of blooms. In early spring, prune your plants to keep them healthy and strong, and they’ll produce a bumper crop of flowers in the summer.


Relatively disease-free. Powdery mildew may show on petals and leaves if planted in super moist soils with low air flow.

St. John’s Wort gets its name from the fact that it flowers on or around St. John’s day on 24 June. It was mainly used in the middle ages as magic potions.


Giant St. John’s Wort – Facts, Identification, Grow and Care

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