Square-stalked St John’s Wort (Hypericum tetrapterum)

Square Stalked St John’s Wort | Hypericum tetrapterum

Native UK marginal pond plant with bright yellow flowers and excellent wildlife value

Square Stalked St John’s Wort, scientifically known as Hypericum tetrapterum, is a beautiful UK native marginal pond plant that naturally thrives around damp meadows, pond edges, ditches, and wetland habitats. With its cheerful bright yellow flowers and fresh green foliage, this low growing perennial is perfect for softening harsh pond edges and creating a more natural transition between water and garden planting.

Flowering from July through to September, this wildlife friendly plant produces masses of nectar rich yellow blooms that attract bees, hoverflies, butterflies, and other important pollinators throughout the summer months. The flowers sit neatly above the plant’s spreading green foliage, creating a relaxed and natural appearance that works beautifully in wildlife ponds, bog gardens, and naturalistic water features.

One of the most appealing features of Hypericum tetrapterum is its ability to gently spread without becoming invasive. Its creeping habit allows it to gradually fill damp spaces around pond margins, helping create dense cover for frogs, newts, beneficial insects, and emerging amphibians. This makes it an excellent choice for wildlife focused pond planting schemes where biodiversity and habitat creation are important.

The square shaped stems, from which the plant gets its common name, add subtle texture and interest throughout the growing season. Combined with its small oval leaves and soft spreading growth habit, this plant blends beautifully alongside other native marginal pond plants and moisture loving perennials.

Square Stalked St John’s Wort is suitable for ponds of almost any size, from smaller wildlife ponds through to larger natural water gardens. It performs particularly well in shallow water or permanently damp soil where it receives full sun or partial shade. Once established, it requires very little maintenance and is extremely hardy in UK conditions.

Its low maintenance nature makes it ideal for gardeners wanting a natural pond edge planting solution without the need for constant trimming or dividing. The plant also helps soften stone edging, gravel margins, and formal pond shelves, giving the pond a far more mature and established appearance.

Whether you are creating a dedicated wildlife pond, natural bog garden, or simply adding more biodiversity around your water feature, Square Stalked St John’s Wort is an excellent native choice that combines ecological value with bright seasonal colour.

🇬🇧 UK-grown aquatic plant: Grown at a dedicated aquatic plant nursery in the South of England and carefully prepared for delivery across the UK.

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Key Benefits

• Native UK marginal pond plant
• Bright yellow flowers attract pollinators
• Excellent for wildlife ponds and bog gardens
• Provides cover for amphibians and insects
• Soft spreading habit helps naturalise pond edges
• Low maintenance and easy to grow
• Suitable for small and large ponds alike
• Hardy and reliable in UK conditions

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Reasons to Buy

• Perfect for creating natural looking pond margins
• Helps support biodiversity around ponds
• Long flowering period through summer
• Excellent companion plant for native pond schemes
• Great choice for wildlife friendly gardens
• Adds colour without becoming overpowering

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Care Instructions

• Square Stalked St John’s Wort grows best in moist soil or shallow water up to 5 cm deep. Position the plant in full sun or partial shade for the strongest flowering performance.
• Keep the soil consistently damp, particularly during warmer summer periods. Once established, this plant is highly resilient and requires very little ongoing maintenance.
• Pruning is rarely necessary, although faded stems can be trimmed back in autumn or early spring to tidy the planting area if desired.
• Divide mature clumps occasionally if you wish to control spreading or encourage fresh vigorous growth.

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Flowering Period

July to September

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Size and Growing Conditions

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Dispatching Your Pond Plants

Your Square-stalked St John’s Wort will be carefully packed to protect the foliage and roots during transit.

Orders received by 11am Monday to Wednesday are normally dispatched on the following working day using a next working day courier service. During busy periods, dispatch may occasionally take an extra day.

To avoid plants being held in depots over a weekend, we do not usually dispatch on Fridays. Highlands and Islands orders using a two day service are not normally dispatched on Thursdays.

Available basket sizes:

• Pack of 3 × 9cm Pots
• 1 Litre Basket – usually 11 × 11 × 11cm square; some varieties may be supplied in a 14cm diameter × 10cm round basket
• Pack of 3 × 1 Litre Baskets – each usually 11 × 11 × 11cm square

Planting depth is measured from the top of the aquatic basket to the water surface.

Plants supplied in 9cm pots require potting into suitable aquatic baskets before being placed in the pond.

Finofil baskets are manufactured in the UK from 100% recycled plastic and are fully recyclable. Their fine dual-mesh construction helps retain aquatic soil while allowing water and nutrients to reach the roots. Basket shape may vary slightly depending on the plant and supplier availability.

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Similar pond plants

For another pond-edge planting option, compare Marsh St John’s Wort (Hypericum elodes) and Star Grass (Rhynchospora colorata, syn. Dichromena colorata).

Explore more marginal pond plants or browse our complete pond plants range. Need baskets, aquatic soil or planting essentials? Browse our pond plant baskets and aquatic planting supplies.