Mock Orange (Philadelphus): Grow and Prune

Philadelphus is one of the most fragrant shrubs you can grow in a British garden. Its common name, mock orange, comes from the scent of its white flowers, which smell just like orange blossom. A single mature bush can scent a whole garden in June and July. It grows on almost any soil, laughs off cold winters and forgives a bit of neglect.

There are lots of species and varieties, but only a handful you really need to know. Here’s which to choose for your space, how to prune it (get this wrong and you lose a year of flowers), and how to make new plants from summer cuttings. Whether you have a cottage garden border or a small paved courtyard, there’s a philadelphus to fit.

Which philadelphus variety should I choose?

Three favourites side by side: compact Belle Etoile, double-flowered Virginal and dwarf Manteau d’Hermine.

Best for small gardens

Manteau d’Hermine stays under 1m, so it’s great in a big pot or at the front of a border. Its double, creamy-white flowers come in dense clusters along arching stems. It’s a handy choice for small gardens where space is tight. Belle Etoile is a little bigger, at about 1.5m, with a purple blush at the heart of each flower.

Best for hedging and screening

P. coronarius is the traditional cottage garden mock orange. It grows quickly to about 4m tall and 3m wide, so it makes a lovely informal hedge. Its creamy flowers open in early June and the scent drifts a long way on a still evening. For a flowering screen, plant 1.5m apart and let the plants grow unpruned for the first three years. After that, remove a third of the oldest stems each year to keep it bushy from top to bottom. It looks great alongside other flowering shrubs in a mixed boundary.

A mature mock orange hedge makes a thick, fragrant boundary between two gardens.

Where to plant philadelphus

Philadelphus grows in almost any soil that drains reasonably well. It’s happy on heavy clay, chalk, loam and sand, which makes it one of the easiest shrubs to place. Give it sun for the best flowers.

Spacing depends on how you’re using it. For a single shrub, allow its full spread plus 30cm each side. For an informal hedge, plant at half its expected spread.

Plant between October and March, while the shrub is dormant. Potted plants can go in at any time, but autumn planting gives the roots months to settle before the first dry summer. Dig a hole twice as wide as the rootball and just as deep. Mix in a handful of bone meal and fill back in with the soil you dug out. Water well and mulch with a thick layer of bark or garden compost.

How to prune philadelphus after flowering

Timing is everything. Philadelphus flowers on stems that grew the summer before. Prune at the wrong time and you cut off the flower buds and lose a whole year of blooms.

Prune within a couple of weeks of the last flowers fading, usually in late July. It’s simple:

1. Find the oldest, thickest stems. They have grey bark and carry the faded flowers.
2. Cut a third of these old stems right down to the ground with loppers or a pruning saw.
3. Leave the young green shoots alone. They’ll carry next year’s flowers.
4. Remove any crossing, dead or damaged branches.
5. Step back and check the shape. You’re aiming for an open, vase-like shrub.

Do this every year and the plant keeps making strong flowering stems. Skip it for a few years and you’ll end up with a thicket of old wood that only flowers at the very top, out of reach and out of sight.

Pruning straight after flowering. Take a third of the oldest stems down to the ground each July.

Rescuing an old, overgrown philadelphus

A philadelphus that’s been left for years usually bounces back from a hard prune. In March, cut the whole plant down to 30cm from the ground. Every stem. It looks brutal, but mock orange is very tough. New shoots soon appear and grow quickly through the summer. Expect a few flowers in the second summer and a full show by the third. Give it a general fertiliser afterwards, following the pack, to help it regrow.

Cut right back to 30cm in March, a tired mock orange sends up strong new shoots like these. Expect a few flowers in the second summer and a full show by the third.

How to propagate philadelphus from cuttings

Semi-ripe cuttings taken in July root easily and give you free plants just like the parent. It works for every variety.

1. Choose a healthy shoot from this year’s growth with no flowers. It should be firm at the base and still soft at the tip.
2. Cut a 10-15cm length, just below a leaf joint.
3. Strip off the lower leaves, leaving two or three pairs at the top.
4. Dip the end in rooting powder if you have some.
5. Push it into a half-and-half mix of perlite and peat-free compost, burying the bottom third.
6. Water lightly. Cover the pot with a clear plastic bag or pop it in a propagator.
7. Roots usually form in four to six weeks. A gentle tug tells you when they have.
8. Pot each one into a 9cm pot in September and keep it in a cold frame or sheltered spot over winter.
9. Plant out the following autumn, once it has a good root system.

Gardener’s tip: Take a few more cuttings than you need, as not every one will root.

Philadelphus care calendar

Common mistakes when growing philadelphus

Pruning in winter or spring. The number one mistake. Every cut removes flower buds that formed the summer before. Always prune straight after flowering.

Planting in deep shade. It copes with light shade but flowers far less without sun.

Too much nitrogen. Lawn feed and fresh manure give you lots of leaves and fewer flowers. Use a balanced fertiliser or a mulch of compost instead. Our best fertilisers for gardens guide has more on feeding shrubs.

Never pruning at all. Left alone for years, it turns into a bare-stemmed thicket that flowers only at the top. Taking out a third of the old stems each year keeps it flowering from the ground up.

Planting too close to walls. Its arching branches need room. Leave at least 60cm between the base and any wall or fence. A cramped plant grows lopsided and gets less air, which makes mildew more likely.

Philadelphus pests and diseases

Powdery mildew shows as a white, dusty coating on leaves in late summer, especially in dry, still weather. It rarely does real harm. Thin out crowded stems to let air through, and water the soil rather than the leaves. Keeping the roots moist in dry spells helps too.

Aphids sometimes gather on soft shoot tips in May and June. A jet of water knocks them off. Encourage ladybirds and lacewings by growing bee-friendly plants and avoiding sprays. Aphids on philadelphus are almost always just cosmetic.

Good companions for philadelphus

Philadelphus is at its best in June and July. Plant some partners around it to keep the area interesting for the rest of the year.

Spring partners: Snowdrops and daffodils carpet the ground beneath it before its leaves open. Brunnera ‘Jack Frost’ adds silver leaves and little blue flowers from April.

Summer partners: Hardy geraniums, especially ‘Rozanne’, flower for months and cover the base of the shrub. Foxgloves add tall spires behind compact varieties. These pairings look great in mixed borders.

Autumn and winter interest: Philadelphus loses its leaves in winter, so add some evergreens for structure. Euonymus or low-growing sarcococca give green bulk from November to March. Sarcococca also has scented winter flowers, keeping the fragrance going all year. Our guide to white flowers for UK gardens has more pairing ideas.

Now you know how to grow and prune philadelphus, read our guide to the best perennial plants for UK gardens for ideas to plant around your mock orange.

Frequently asked questions

When should I prune philadelphus?

Straight after flowering, usually in July. Philadelphus flowers on stems that grew the summer before. Cut a third of the oldest, thickest stems to the ground each year. This gets strong new shoots going for next year’s flowers. Never prune in winter or early spring, or you’ll cut off the flower buds.

Can philadelphus grow in shade?

It copes with part shade but flowers best in full sun. In deep shade it gets leggy and flowers poorly. The sunnier the spot, the more flowers and scent you’ll get.

How do I take cuttings from philadelphus?

Take semi-ripe cuttings in July. Choose healthy shoots 10-15cm long with no flowers. Strip the lower leaves, dip in rooting powder if you have some, and push into a half-and-half mix of perlite and peat-free compost. Cover with a clear plastic bag. Roots usually form in four to six weeks. Pot them up separately in autumn.

Why is my philadelphus not flowering?

Pruning at the wrong time is the usual cause. Cutting it in winter or spring removes the flower buds made the summer before. Too much shade, too much nitrogen-rich feed and very young plants can also mean few flowers.

How big does philadelphus grow?

It depends on the variety. Manteau d’Hermine stays under 1m and Belle Etoile reaches about 1.5m. Virginal grows to around 3m, and P. coronarius can reach 4m tall and 3m wide. Yearly pruning helps keep any of them in shape.

Is philadelphus good for wildlife?

Yes, bees and hoverflies visit the flowers. Single-flowered varieties, with their open centres, are easiest for pollinators to feed from. The dense branches also give small birds somewhere to shelter and nest.

Can I hard prune an old overgrown philadelphus?

Yes, it takes a hard prune well. Cut the whole shrub down to 30cm from the ground in March. It soon sends up lots of new shoots and should be flowering well again within a couple of years. It’s the quickest fix for a tired plant that’s bare at the bottom.