Passion Flower Clematis

Clematis florida Sieboldii is an extraordinary climbing clematis prized for its distinctive passion flower-like blooms and vigorous habit. Known affectionately as the Passion Flower Clematis, this deciduous climber delivers a spectacular floral display from early summer into autumn. It is superb for adding height, drama, and elegance to UK gardens. Whether grown over a trellis, archway, or obelisk, ‘Sieboldii’ rewards gardeners with beauty and resilience.

In this guide, we’ll explore the fascinating history, standout floral features, ideal growing conditions, and essential care tips for Clematis florida ‘Sieboldii’—and why this unforgettable clematis deserves a prominent place in your garden.

Native to parts of Japan and China, Clematis florida is known for its refined form and intricate floral structure. The cultivar ‘Sieboldii’ is named in honour of German botanist Philipp Franz von Siebold, who pivotally introduced many Asian plants to Europe during the 19th century. His legacy lives on in this exceptional clematis, which has become a beloved favourite among collectors and garden designers.

Its heritage gives it a natural elegance, while its ease of cultivation ensures it appeals to gardeners of all experience levels. Over time, ‘Sieboldii’ has become a standout selection in clematis collections thanks to its eye-catching appearance and versatility in various garden settings.

It’s spectacular, bicoloured flowers set Clematis florida Sieboldii apart. Each blossom features creamy-white sepals surrounding a central boss of deep purple, almost thistle-like stamens, creating a striking contrast that evokes the exotic beauty of passion flowers. The blooms typically measure 7–10 cm (3–4 inches) across and appear freely on new growth, making each summer an anticipated spectacle.

These dramatic flowers emerge in waves from June through September, bringing dynamic, exotic charm to vertical planting schemes. The rich, dark green foliage—comprising trifoliate, serrated leaves—provides the perfect backdrop to enhance the visual impact of the blooms, ensuring Clematis florida ‘Sieboldii’ remains the garden star throughout the season.

This clematis thrives in various garden environments, making it a versatile addition to urban courtyards and sprawling country plots. To achieve the most prolific flowering, plant ‘Sieboldii’ in a location with full sun to partial shade, ensuring it receives at least six hours of sunlight daily. While it will tolerate light shade, sunnier conditions encourage more abundant and richly coloured blooms.

Plant in well-drained, fertile soil enriched with organic matter. Clematis prefer their roots cool and shaded, while the upper growth enjoys the sun—an ideal setup can be achieved by planting groundcover around the base or using mulch to retain moisture and regulate temperature. Soil pH should ideally be neutral to slightly alkaline, though this adaptable plant will also perform well in mildly acidic soils with good structure.

Clematis florida Sieboldii is reliably hardy across most parts of the UK, tolerating winter lows of around –15°C (5°F). In colder inland or northern areas, a sheltered position and mulching in winter can help protect the roots and emerging buds from frost damage. Its resilience and floriferous nature make it an excellent choice for temperate gardens looking to maximise vertical interest.

Choose a supportive structure such as a pergola, wall trellis, or freestanding obelisk where the plant can climb and display its flowers at eye level. Prepare the planting site by digging a generous hole—roughly twice the size of the root ball—and enriching the soil with well-rotted manure or compost. Position the plant with the crown (where stems meet roots) approximately 5 cm (2 inches) below soil level. This planting depth helps guard against clematis wilt and encourages strong basal growth.

Water thoroughly after planting and provide a cane or guide wire for the young stems to latch onto. Water regularly during dry spells in the first year to ensure healthy root establishment. Once established, ‘Sieboldii’ is moderately drought-tolerant, though it appreciates consistent moisture in warmer months.

Feed your clematis in early spring with a balanced, slow-release fertiliser to promote lush growth and flower bud formation. In the summer, feed every two weeks with a high-potassium liquid feed, such as liquid tomato fertiliser, to encourage prolific flowering. Apply a thick mulch of well-rotted manure in spring to suppress weeds and lock in moisture.

Avoid disturbing the roots once established, and refresh mulch annually to protect the root system and improve soil structure over time.

Clematis florida Sieboldii belongs to Pruning Group 3, which flowers on new growth produced in the current season. To maintain a tidy shape and ensure abundant blooms, cut back all stems each year to a strong pair of buds, approximately 20–30 cm (8–12 inches) above ground level. Perform this task in late winter or early spring before the plant breaks dormancy.

Pruning promotes vigorous new shoots, helps control size, and prevents woody or leggy growth. Use soft ties to gently train new stems along the chosen support, encouraging an even and elegant display.

While generally trouble-free, ‘Sieboldii’ can occasionally be affected by common garden pests such as aphids or spider mites, especially in hot, dry conditions. Aphid infestations can be controlled using insecticidal soap or attracting natural predators like ladybirds.

Clematis wilt, a fungal disease causing sudden stem collapse, is a known risk for this species. Planting deeply, ensuring good airflow around the plant, and avoiding overhead watering are all helpful preventative measures. If wilt appears, please remove affected stems and dispose of them from the garden to reduce the spread.

From early summer to early autumn, Clematis florida ‘Sieboldii’ delivers exceptional seasonal interest, acting as a living sculpture within the garden. Its elegant blooms suit traditional cottage gardens and contemporary planting schemes, offering flexibility across styles.

Use it to cover unsightly structures, elevate fences, or create a sense of drama in vertical features such as pergolas and arches. Pair it with late-flowering roses, evergreen climbers, or complementary clematis cultivars with contrasting hues for added visual intrigue. Its refined colour palette works especially well against pale or dark backgrounds, where the flowers can be fully appreciated.

Clematis florida ‘Sieboldii’ is more than just a climber—it is a botanical statement piece. Combining ornamental flair with robust garden performance, it offers long-lasting beauty, low-maintenance care, and broad design potential. Whether enhancing a small courtyard or refining a larger border, ‘Sieboldii’ brings structure, texture, and colour to the vertical plane.

As a fast-growing perennial climber with a reliable flowering habit, it deserves a permanent place in the well-planned garden. Its rich cultural heritage also appeals to gardeners with a passion for plants of historical and botanical significance.

Clematis florida ‘Sieboldii’ never fails to stop visitors in their tracks. There’s something truly special about those exotic, passion flower-like blooms—each one like a tiny work of art. I grow mine on an obelisk near a seating area to enjoy the flowers up close through summer. It’s a real talking point, but also a reliable performer. As long as it gets good light and the roots stay cool, it rewards me wave after wave of flowers. The pruning couldn’t be simpler either—just a good, hard cut in late winter, and it bounces back stronger each year. If you’re looking for a climber with drama, elegance, and a bit of botanical heritage, this one’s a gem.

• Striking Blooms: Features creamy white petals with a dramatic central boss of rich purple stamens, resembling passion flowers.
• Long Flowering Season: Blooms from early summer to early autumn, offering months of vibrant garden colour.
• Ideal Growing Conditions: Prefers full sun to partial shade and thrives in well-drained, fertile soil with a neutral to slightly alkaline pH.
• Hardy and Adaptable: Tolerates UK winters to around -15°C (5°F), making it suitable for most garden climates.
• Pruning Group 3: This group requires annual hard pruning in late winter or early spring to encourage strong growth and prolific flowering.
• Climbing Habit: Perfect for training up trellises, pergolas, arches, or fences; adds vertical interest and visual drama.
• Low Maintenance: Generally pest- and disease-resistant, with minimal care needs once established.
• Heritage Cultivar: Named after botanist Philipp Franz von Siebold, this variety has a rich botanical history and enduring appeal.
• Excellent Companion Plant: Combines beautifully with roses, shrubs, and other climbers for layered planting designs.
• Wildlife Friendly: Attracts pollinators, contributing to garden biodiversity and ecological value.

Clematis florida Sieboldii offers an exceptional blend of exotic beauty, reliable performance, and garden versatility. With its striking passion flower-like blooms, elegant climbing habit, and long flowering season, this captivating clematis brings a touch of drama and sophistication to any outdoor space.

Whether you want to enhance a wall, trellis, or pergola or simply introduce more colour and vertical interest to your planting scheme, Sieboldii is a standout choice. Its hardiness, adaptability, and manageable care requirements make it suitable for both novice gardeners and experienced plant enthusiasts.

By providing the right conditions, regular pruning, and a little seasonal care, you’ll be rewarded year after year with a spectacular display that turns heads and elevates your garden design. Add Clematis florida ‘Sieboldii’ to your garden and enjoy a truly unique climber that combines heritage, elegance, and floral brilliance in one unforgettable package.

Explore our full collection of planting guides for expert advice on climbers and wall shrubs.

Want to learn about other climbers? Read about Clematis montana Rubens here.

Q: What makes Clematis ‘Sieboldii’ special?

A: This stunning clematis features white flowers with deep purple centres that resemble a fancy pin cushion. Each bloom measures about 8-10cm across, creating a dramatic display against the green foliage.

Q: How tall does ‘Sieboldii’ grow?

A: This compact climber reaches 2-3 metres (6-10 feet) in height. The manageable size makes it perfect for containers, small gardens, or growing through shrubs and roses.

Q: When does it flower?

A: ‘Sieboldii’ produces flowers from early summer to early autumn. The main flush occurs in June-July, often followed by a second flowering period in September.

Q: What growing conditions does it prefer?

A: Plant in rich, well-drained soil with the roots in cool shade and the stems climbing into sunlight. Morning sun with afternoon shade provides ideal conditions.

Q: How hardy is ‘Sieboldii’?

A: This clematis withstands temperatures below -15°C (5°F). In colder areas, a thick mulch layer provides winter protection for the roots.

Q: What pruning does it need?

A: Prune in early spring, cutting all stems back to about 30cm (12 inches) above ground level. This hard pruning promotes strong new growth and abundant flowers.

Q: Can I grow it in containers?

A: ‘Sieboldii’ grows beautifully in at least 45cm (18 inches) deep containers. Use good-quality soil-based potting compost and ensure excellent drainage.

Q: How do I prevent clematis wilt?

A: Plant deeply with the crown 5-7cm (2-3 inches) below soil level. Good air circulation and proper watering help prevent this common problem.

Q: What support does it need?

A: Provide sturdy trellis, wires, or plant alongside host shrubs. The slender stems need regular tying in during the growing season.

Q: How often should I water and feed?

A: Water regularly, especially during dry spells and the first growing season. Apply a balanced fertiliser in spring and summer to encourage healthy growth and flowering.