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Ornamentalshrub ornamentalStraightforward

Mock orange

Philadelphus coronarius

Grown for about three weeks in June and worth the other forty-nine for the scent alone, which is the strongest of any hardy shrub in a British garden and carries a surprising distance on a warm evening. Ungainly out of flower, so it belongs at the back of a border rather than as a specimen.

Position
Full sun or Partial shade
Water
low demand
Drainage
Free-draining, Moisture-retentive
Grows to
200–300 cm × 150–250 cm
Hardiness
H6
Flowers
June and July
Difficulty
Straightforward

August

Prune

Mock orange’s year

Resolved for United Kingdom (general). Every window is stored against a climate event rather than a date, so a late frost pocket runs later than the band shows. What else August calls for.

ActivityJFMAMJJASOND
PlantMarch. October. November.
In flowerJune. July.
PruneJuly. August.

Names that cause confusion

mock orange — Also used for Choisya ternata, the Mexican orange blossom, which is an evergreen and an entirely different plant. Philadelphus is deciduous and flowers once, in June, with a scent that carries across a garden.

Timing that travels

The band above resolves this plant's windows into months for one region. These are the windows themselves, stored against a climate event rather than a date — which is the form that survives being carried to a colder garden, a frost pocket, or next year.

Conditions it needs

Light
Full sun, Partial shade
Frost
Very hardy
Hardiness rating
H6 (RHS)
Grows best at
12–26 °C
Soil
Loam, Chalky, Sandy, Clay
Soil pH
6–8
Drainage
Free-draining, Moisture-retentive
Water needs
low
Drought
good tolerance
Waterlogging
poor tolerance
Heat
good tolerance
Wind and exposure
moderate tolerance
Where these figures come from
LightSourced guidancemoderate confidence
  • Royal Horticultural Society: Philadelphus — position

Checked 2026-08-13

FrostSourced guidancehigh confidence
  • Royal Horticultural Society: Philadelphus — hardiness

Checked 2026-08-13

Hardiness ratingSourced guidancemoderate confidence
  • Royal Horticultural Society: RHS hardiness ratings

Checked 2026-08-13

Grows best atSourced guidancemoderate confidence
  • Royal Horticultural Society: Philadelphus — temperature

Checked 2026-08-13

SoilSourced guidancemoderate confidence
  • Royal Horticultural Society: Philadelphus — soil

Checked 2026-08-13

Soil pHSourced guidancemoderate confidence
  • Plant Finder — Missouri Botanical Garden: Philadelphus coronarius — culture

Checked 2026-08-13

DrainageSourced guidancemoderate confidence
  • Royal Horticultural Society: Philadelphus — soil

Checked 2026-08-13

Water needsHorticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

DroughtHorticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

WaterloggingHorticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

HeatHorticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

Wind and exposureHorticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

On your soil

Computed by comparing this plant's recorded requirements against each soil's recorded characteristics. A recorded horticultural fact overrides the comparison where GrowingHQ holds one.

SoilVerdictWhy
Heavy clayWorks, with one conditionMock orange will crop on heavy clay, but one thing has to be dealt with first. It needs ground that drains, and this soil holds water. A plant that stays in the ground through winter with its roots in cold, saturated soil rots — which is what kills most of what fails on heavy ground, rather than the cold.Improve the drainage before planting — a raised bed, or bulky organic matter worked in over several seasons. Do not add sand to clay in small quantities; it makes the problem worse.
SandyPrefers this soilSandy suits Mock orange as it stands: The pH suits it: it wants 6 to 8, and this soil is in that range. The free drainage is exactly what it wants. Sandy soil is among the soils it is recorded as suiting. It stands dry conditions better than most, which this soil will test.
Chalky and alkalinePrefers this soilChalky and alkaline suits Mock orange as it stands: The free drainage is exactly what it wants. Chalky soil is among the soils it is recorded as suiting. It stands dry conditions better than most, which this soil will test.
LoamPrefers this soilLoam suits Mock orange as it stands: The pH suits it: it wants 6 to 8, and this soil is in that range. The free drainage is exactly what it wants. Loam is among the soils it is recorded as suiting. The soil holds moisture, which saves a great deal of watering.
SiltyPrefers this soilSilty suits Mock orange as it stands: The pH suits it: it wants 6 to 8, and this soil is in that range. The free drainage is exactly what it wants. The soil holds moisture, which saves a great deal of watering.
Peaty and acidWorks, with one conditionMock orange will crop on peaty and acid, but one thing has to be dealt with first. It needs ground that drains, and this soil holds water. A plant that stays in the ground through winter with its roots in cold, saturated soil rots — which is what kills most of what fails on heavy ground, rather than the cold.Improve the drainage before planting — a raised bed, or bulky organic matter worked in over several seasons. Do not add sand to clay in small quantities; it makes the problem worse.
Shallow over rockPrefers this soilShallow over rock suits Mock orange as it stands: The free drainage is exactly what it wants. Loam is among the soils it is recorded as suiting. It stands dry conditions better than most, which this soil will test.
Made ground and urban soilWorks, with one conditionMock orange will crop on made ground and urban soil, but one thing has to be dealt with first. It needs ground that drains, and this soil holds water. A plant that stays in the ground through winter with its roots in cold, saturated soil rots — which is what kills most of what fails on heavy ground, rather than the cold.Improve the drainage before planting — a raised bed, or bulky organic matter worked in over several seasons. Do not add sand to clay in small quantities; it makes the problem worse.

Not sure which you have? Four hand tests will settle it.

Space and spacing

Mature height
200–300 cm
Mature spread
150–250 cm
Rooting depth
60 cm
Spacing
150–200 cm apart
Where these figures come from
Mature heightHorticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

Mature spreadHorticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

Rooting depthHorticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

SpacingSourced guidancemoderate confidence
  • Royal Horticultural Society: Philadelphus — spacing

Checked 2026-08-13

How far apart to plant mock orangeThree mock orange plants drawn in a row at their recorded spacing of 150–200 cm between plants. The spacing is drawn to scale against a one metre rule; the plants themselves are symbols rather than scale drawings, so the distance between them is the part to read.150–200 cmone metre
Measured centre to centre. Plants set closer than this compete for light and water long before they look crowded, and the crowding cannot be undone once they are in.

Habit and ultimate size

What the plant becomes, rather than what it is when you buy it. The gap between the two is where most planting mistakes live.

Foliage
Deciduous
In a container
Not a realistic container plant
Where these figures come from
FoliageSourced guidancehigh confidence
  • Royal Horticultural Society: Philadelphus coronarius — foliage

Checked 2026-08-13

In a containerHorticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

Growth rate
Fast — over about 60 cm a year
Ultimate height
200–300 cm
Ultimate spread
150–250 cm
Time to reach it
10–15 yearsSourced guidance
Where these figures come from
Growth rateSourced guidancemoderate confidence
  • Royal Horticultural Society: Philadelphus coronarius — growth rate

Checked 2026-08-13

Ultimate heightSourced guidancemoderate confidence
  • Royal Horticultural Society: Philadelphus coronarius — ultimate height

Checked 2026-08-13

Ultimate spreadSourced guidancemoderate confidence
  • Royal Horticultural Society: Philadelphus coronarius — ultimate spread

Checked 2026-08-13

Time to reach itSourced guidancelow confidence
  • Royal Horticultural Society: Philadelphus coronarius — time to ultimate size

Checked 2026-08-13

Cutting it back. One of the most reliable shrubs for hard renovation: cut everything to 30 cm in winter and it rebuilds completely in two seasons. Worth knowing because a neglected philadelphus becomes bare-legged and ungainly faster than most.
source

Horticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

Where and how you can grow it

Each way of growing is assessed separately, and “not assessed” is a real answer rather than a gap we have filled in with a guess.

MethodSuitabilityWhat it needs
Open groundWell suited
source

Sourced guidancemoderate confidence

  • Royal Horticultural Society: Growing method suitability

Checked 2026-08-13

Traditional dug bedWell suited
source

Sourced guidancemoderate confidence

  • Royal Horticultural Society: Growing method suitability

Checked 2026-08-13

Raised bedWell suited
source

Sourced guidancemoderate confidence

  • Royal Horticultural Society: Growing method suitability

Checked 2026-08-13

ContainerMarginal
source

Sourced guidancemoderate confidence

  • Royal Horticultural Society: Growing method suitability

Checked 2026-08-13

Growing it

  • PruningTake a third of the oldest stems out at ground level as soon as flowering ends, and leave the rest alone. Philadelphus flowers on last year's wood and rejuvenates readily from the base, so this rolling replacement keeps a plant permanently furnished — whereas shortening all the branches produces a bare-legged shrub with a mop of twigs on top and few flowers.
  • PlantingOne of the better shrubs for thin chalky soil, where a great many flowering shrubs sulk. It is genuinely happier on alkaline ground than on heavy wet clay.
Where this guidance comes from
PruningSourced guidancehigh confidence
  • Royal Horticultural Society: Philadelphus — pruning

Checked 2026-08-13

PlantingSourced guidancemoderate confidence
  • Royal Horticultural Society: Philadelphus — soil

Checked 2026-08-13

Where to make a pruning cutFour stems compared. The first is cut cleanly on a slope about five millimetres above an outward-facing bud, sloping away from it, and is labelled correct. The second is cut too far above the bud, leaving a long stub that dies back. The third is cut too close, into the bud itself, which loses the shoot. The fourth is cut sloping towards the bud so rain runs onto it rather than away, which rots it. In every case the bud points outwards, away from the centre of the plant.Correct5 mm, sloping awayToo highstub dies backToo closebud lostSloping inrain sits on the bud
The bud you cut to becomes the new shoot, and it grows in the direction it points — which is why an outward-facing bud opens the plant up and an inward-facing one crosses the middle.

Sources for this page

GrowingHQ editorial synthesis · Plant Finder · Royal Horticultural Society

Each figure on this page carries its own citation, under the “where these figures come from” note in its section. Record last reviewed 2026-08-14.