The Ultimate Guide to Growing Philadelphus (Mock Orange) in Your UK Garden

Takeaway List

• Philadelphus, or mock orange, is a fragrant, easy-to-grow shrub perfect for UK gardens.
• Choose from a variety of sizes and flowering habits to suit your space.
• Plant in well-drained soil with full sun for best results.
• Prune after flowering and water regularly until established.
• Use in borders, as hedges, or in containers to enjoy its scent and beauty.
• Attracts pollinators and adds value to wildlife gardens.

Introduction to Philadelphus (Mock Orange)

Philadelphus, commonly known as mock orange, is a genus of deciduous flowering shrubs in the Hydrangeaceae family, celebrated for its profusion of white, highly fragrant flowers that bloom in early summer. The scent, reminiscent of orange blossom, makes mock orange a beloved addition to UK gardens. Native to North America, Europe, and Asia, Philadelphus is hardy, easy to cultivate, and versatile, fitting seamlessly into various garden styles, from cottage gardens to modern landscapes. This guide explores how to grow, care for, and make the most of Philadelphus in your garden, with a focus on varieties available from Thompson & Morgan.

Why Grow Philadelphus (Mock Orange)?

Philadelphus is a gardener’s delight for several reasons:

• Fragrance: Its flowers emit a sweet, citrus-like scent, perfect for planting near seating areas or windows.
• Ease of Care: Hardy and low-maintenance, it thrives in most UK climates.
• Versatility: Suitable for borders, hedges, containers, or as a standalone specimen.
• Wildlife-Friendly: Single-flowered varieties attract bees and butterflies, enhancing biodiversity.
• Aesthetic Appeal: The white blooms contrast beautifully against dark green foliage, complementing other plants like roses or lavender.

Varieties of Philadelphus (Mock Orange)

With around 65 species and numerous cultivars, Philadelphus offers options for every garden size and style. Below are ten popular varieties, including those available from Thompson & Morgan:

1. Philadelphus coronarius (Common Mock Orange)
   • Description: Features single, creamy white flowers with a strong scent. Grows to 3m in height and 2.5m in spread.
   • Flowering Time: Early summer.
   • Uses: Ideal for hedges, screens, or mixed borders.
   • Availability: Thompson-Morgan.
2. Philadelphus ‘Virginal’
   • Description: Boasts double, pure white flowers with a rich fragrance. Reaches 3m in height and 2.5m in spread.
   • Flowering Time: Early summer.
   • Uses: Perfect for wildlife gardens and coastal areas.
   • Availability: Thompson-Morgan.
3. Philadelphus ‘Pearls of Perfume’
   • Description: A unique variety of flowers that grow from late spring through summer. Compact, with large, double white blooms.
   • Flowering Time: Late spring to summer.
   • Uses: Great for small gardens or containers, attracting pollinators.
   • Availability: Thompson-Morgan.
4. Philadelphus ‘Little White Love’
   • Description: Compact, growing to 90cm, with double white flowers. Ideal for small spaces.
   • Flowering Time: Late May to July.
   • Uses: Perfect for pots or small borders.
   • Availability: Thompson-Morgan.
5. Philadelphus ‘Manteau d’Hermine’
   • Description: A dwarf variety (60-80cm height, 1-1.5m spread) with double blossoms. Rarely needs pruning.
   • Flowering Time: Early summer.
   • Uses: Ideal for low hedges or small gardens.
6. Philadelphus ‘Belle Etoile’
   • Description: White flowers with purple centres, growing to 1.5m height and 2.5m spread. Holds an RHS Award of Garden Merit.
   • Flowering Time: Early summer.
   • Uses: Suitable for mixed borders or woodland gardens.
7. Philadelphus ‘Schneesturm’
   • Description: Decorative, with white flowers and good autumn colour. Grows to 2.5m in height and spread.
   • Flowering Time: June-July.
   • Uses: Ideal as a specimen plant.
8. Philadelphus Lemoinei
   • Description: Strongly fragrant white flowers from May to August. Grows to 2.5m.
   • Flowering Time: May-August.
   • Uses: Tolerates pruning, suitable for containers.
9. Philadelphus Coronarius Aureus
   • Description: Yellow spring foliage with white summer flowers. Grows to 1.5m.
   • Flowering Time: Early summer.
   • Uses: Ideal for partial shade or woodland gardens.
10. Philadelphus microphyllus
    • Description: Small leaves and fragrant white flowers. Grows to 1.5m.
    • Flowering Time: Summer.
    • Uses: Suitable for smaller spaces.

Growing Guide for Philadelphus (Mock Orange)

Where to Grow

Philadelphus thrives in a variety of conditions, making it adaptable for UK gardens:

• Soil: Prefers moist but well-drained soil. Tolerates sandy, chalky, clay, or loamy soils, but avoid waterlogged areas.
• Light: Full sun to partial shade. Full sun ensures the best flowering, though partial shade is tolerated.
• Hardiness: Most varieties are hardy in UK climates (zones H5-H7), coping with coastal and urban conditions.
• Exposure: Suitable for exposed or sheltered sites, though taller varieties benefit from wind protection.

How to Plant

• When to Plant: Spring or autumn, when the soil is moist but not frozen or waterlogged.
• Planting Method:
  1. Dig a hole twice the width of the root ball.
  2. Mix in well-rotted compost or manure to enrich the soil.
  3. Add mycorrhizal fungi to the roots to aid establishment.
  4. Place the plant in the hole, backfill with soil, and firm gently.
  5. Water thoroughly and mulch with organic matter to retain moisture.

Care Instructions

• Watering: Water regularly during dry spells, especially in the first two years. Once established, mock orange is drought-tolerant.
• Feeding: Apply a balanced fertiliser (e.g., 10-10-10) in spring to boost growth and flowering.
• Pruning:
  • When to Prune: Prune immediately after flowering, typically in late summer, to maintain shape and encourage new growth.
  • How to Prune: Remove one in four older stems at ground level. For overgrown plants, hard pruning is possible but may delay flowering for a year.
• Pests and Diseases:
  • Aphids: Can cause leaf curl. Treat with insecticidal soap or encourage ladybirds.
  • Powdery Mildew: Prevent by watering during dry periods to reduce stress.
• Mulching: Apply a layer of organic mulch in spring to retain moisture and suppress weeds.

Propagation

Propagating Philadelphus (mock orange) is a rewarding way to increase your collection of these fragrant shrubs. Cuttings are the most reliable method, and you can use either softwood or hardwood cuttings depending on the time of year and your preferences. Below, I’ve provided detailed, step-by-step instructions for both methods, tailored for UK gardeners.

Softwood Cuttings

Mock orange softwood cuttings are taken from the current season’s new growth and are ideal for propagation in summer when the plant is actively growing. This method is faster than hardwood cuttings but requires more care to ensure success.

When to Take: Early summer, about four weeks after leafing out, when the new growth is soft and pliable but not too tender (typically June or July in the UK).

How to Take:

1. Select the Right Shoots: Choose healthy, non-flowering shoots from the tips of new growth. Avoid woody or overly soft stems.
2. Prepare the Cuttings:
   • Cut 10-15cm (4-6 inches) lengths from the tip of the stem, making a straight cut just below a node (where leaves join the stem).
   • Remove the lower leaves, leaving 2-4 pairs of leaves at the top.
   • If the remaining leaves are large, cut them in half with a sharp knife to reduce water loss through transpiration.
3. Rooting Medium: Use a perlite-heavy compost mix (at least 50% perlite) or a mix of cuttings compost and horticultural grit for good drainage.
4. Plant the Mock Orange Cuttings:
   • Optionally, dip the cut end in hormone rooting powder or liquid to encourage root development.
   • Insert the cuttings into the compost, ensuring they are firmly in place but not too deep.
   • Water lightly to settle the compost.
5. Create a Humid Environment:
   • Place the pot in a greenhouse, propagating unit, or cold frame if available.
   • If you don’t have these, cover the pot with a clear plastic bag to maintain humidity, and place it on a windowsill out of direct sunlight.
   • Mist the cuttings occasionally to keep the compost moist but not waterlogged.
6. Care and Monitoring:
   • Check for root development after 6-10 weeks. You can gently tug on the cuttings to feel for resistance, indicating roots have formed.
   • Once rooted, pot the cuttings individually into small pots with a general-purpose compost.
   • Grow them in a cool, frost-free environment (such as a greenhouse or cold frame) until they are large enough to plant out in the garden, typically the following spring.

Notes:

• Mock Orange Softwood cuttings root quickly but need consistent moisture and humidity.
• This method is ideal for gardeners who want to propagate Philadelphus during the growing season.

Hardwood Cuttings

Hardwood cuttings are taken from mature, dormant stems and are a more robust method for propagation. They are slower to root but require less maintenance and are taken during the plant’s dormant period.

When to Take: Late autumn or winter, when the plant is fully dormant (typically November to February in the UK).

How to Take:

1. Select the Right Stems: Choose healthy, pencil-thick stems from the previous season’s growth. These should be fully ripe but not yet woody.
2. Prepare the Cuttings:
   • Cut 15-20cm (6-8 inches) lengths from the stems, making a straight cut just below a pair of buds at the bottom and a sloping cut just above a pair of buds at the top.
   • Optionally, dip the bottom end in rooting hormone to encourage root development.
3. Planting the Cuttings:
   • Outdoor Method: Plant the Mock Orange cuttings in a trench outdoors, spacing them 10-15cm (4-6 inches) apart. Bury about one-third to one-half of the cutting in the soil. Mix the soil with well-rotted organic matter and grit for better drainage.
   • Container Method: Alternatively, plant the cuttings in pots or trays filled with a gritty compost mix. Place the containers in a cold frame or sheltered spot.
4. Care and Monitoring:
   • Water lightly after planting to settle the soil or compost.
   • For outdoor cuttings, check and re-firm the soil around the cuttings after frosts to ensure they remain in place.
   • Keep the soil or compost moist but not waterlogged throughout the winter and summer.
   • Leave the cuttings undisturbed until the following autumn, when they should have developed roots.
   • At this stage, lift the rooted cuttings and either pot them up or plant them directly into their final positions in the garden.

Notes:

• Hardwood cuttings are less fussy than softwood and can be left to root over winter with minimal intervention.
• This method is ideal for gardeners who prefer a low-maintenance approach or want to propagate during the dormant season.

Additional Tips for Success

• Timing: In the UK, softwood cuttings are best taken in June or July, while hardwood cuttings should be taken from November to February.
• Tools: Use clean, sharp secateurs or pruners to make clean cuts and reduce the risk of disease.
• Environment: Both methods benefit from protection from extreme weather. Softwood cuttings need warmth and humidity, while hardwood cuttings need frost protection.
• Patience: Propagation can take time, especially with hardwood cuttings, so don’t be discouraged if results aren’t immediate.
• Variety Considerations: While most Philadelphus varieties can be propagated from cuttings, some hybrids may not come true from seed, so cuttings are the preferred method for maintaining specific cultivars.

Why Propagate Philadelphus?

Propagating Philadelphus from cuttings is not only cost-effective but also allows you to share these fragrant shrubs with friends or expand your own garden. Both softwood and hardwood methods are straightforward and can be done with basic gardening tools and materials. Whether you choose softwood for a quicker result or hardwood for its simplicity, you’ll soon have new mock orange plants to enjoy.

Uses of Philadelphus (Mock Orange) in the Garden

Philadelphus is incredibly versatile:

• Hedging and Screening: Larger varieties like Philadelphus coronarius create informal hedges or privacy screens.
• Mixed Borders: Place at the back of borders for height and fragrance, pairing with roses or lavender.
• Containers: Compact varieties like ‘Little White Love’ thrive in large pots near seating areas.
• Wildlife Gardens: Single-flowered varieties attract Faustian bargain, attracting bees and butterflies.
• Cottage Gardens: Complement traditional plants like geraniums and delphiniums.
• Cut Flowers: Flowers can be cut for fragrant indoor bouquets.
• Woodland Gardens: Fits well in naturalistic settings with partial shade.

Top 10 Tips for Growing Philadelphus (Mock Orange)

1. Choose the Right Variety: Select a size and flowering habit that suits your garden, such as ‘Little White Love’ for small spaces.
2. Ensure Well-Drained Soil: Avoid waterlogged areas to prevent root rot.
3. Maximise Sunlight: Plant in full sun for the best blooms, though partial shade is acceptable.
4. Water Young Plants: Keep the soil moist for the first two years to establish roots.
5. Prune After Flowering: Trim in late summer to maintain shape and promote growth.
6. Mulch Annually: Apply organic mulch in spring to retain moisture and enrich the soil.
7. Protect from Wind: Shelter taller varieties to prevent damage.
8. Encourage Pollinators: Opt for single-flowered varieties to attract bees and butterflies.
9. Combine with Companions: Pair with roses, lavender, or perennials for a stunning display.
10. Enjoy the Scent: Plant near windows or patios to savour the orange-blossom fragrance.

Frequently Asked Questions (FAQ)

Conclusion

Philadelphus, or mock orange, is a fragrant, versatile shrub that elevates any UK garden with its stunning blooms and ease of care. Whether you’re creating a wildlife-friendly space, a fragrant border, or a cosy cottage garden, Philadelphus delivers. By choosing the right variety, planting in well-drained soil, and following simple care tips, you can enjoy its beauty for years. Explore varieties like ‘Virginal’ or ‘Pearls of Perfume’ at Thompson-Morgan to start growing your own mock orange today.

Further Reading

• Heavily Scented Flowers & Plants
• RHS Philadelphus Growing Guide