Tree or shrubtree ornamentalSome care needed

Magnolia

Magnolia × soulangeana

Enormous goblet flowers on bare branches in April, and a plant whose entire annual performance can be destroyed in one cold night. Where it works it is the most spectacular thing in a British spring garden; where a late frost is routine, it is a fortnight of brown petals a year.

Position: Full sun or Partial shade
Water: moderate demand
Drainage: Moisture-retentive
Grows to: 400–800 cm × 400–800 cm
Hardiness: H5
Flowers: April and May
Difficulty: Some care needed

August

Prune

Coming next month: plant.

Magnolia’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.

Activity	M	A	M	J	A	S	O
Plant	March.	April.				September.	October.
In flower		April.	May.
Prune				July.	August.

Names that cause confusion

tulip tree — Properly belongs to Liriodendron tulipifera, a very large forest tree quite unlike a magnolia. Applied to Magnolia × soulangeana because of the flower shape.

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: Hardy
Hardiness rating: H5 (RHS)
Grows best at: 10–25 °C
Soil: Loam, Clay, Peat-free compost
Soil pH: 5–6.8
Drainage: Moisture-retentive
Water needs: moderate
Drought: poor tolerance
Waterlogging: poor tolerance
Heat: moderate tolerance
Wind and exposure: poor tolerance

Where these figures come from

LightSourced guidancemoderate confidence

Royal Horticultural Society: Magnolia — position

Checked 2026-08-13

FrostSourced guidancehigh confidence

Royal Horticultural Society: Magnolia — 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: Magnolia — temperature

Checked 2026-08-13

SoilSourced guidancemoderate confidence

Royal Horticultural Society: Magnolia — soil

Checked 2026-08-13

Soil pHSourced guidancemoderate confidence

Plant Finder — Missouri Botanical Garden: Magnolia × soulangeana — culture

Checked 2026-08-13

DrainageSourced guidancemoderate confidence

Royal Horticultural Society: Magnolia — 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

Wind shreds the flowers and the large soft leaves.

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.

Soil	Verdict	Why
Heavy clay	Works, with one condition	Magnolia 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.
Sandy	Works, with one condition	Magnolia will crop on sandy, but one thing has to be dealt with first. It has little drought tolerance and this soil dries out fast — it will check and bolt in the first dry spell without watering.Water and mulch will carry it through. On this soil the watering is not optional in a dry spell, which is the difference between a crop and a failure.
Chalky and alkaline	Struggles here	Magnolia struggles on chalky and alkaline: The soil is substantially too alkaline for it: it wants pH 5 to 6.8, and this soil sits around 7.8 to 8.5. It has little drought tolerance and this soil dries out fast — it will check and bolt in the first dry spell without watering. A container or a raised bed of imported soil sidesteps the problem entirely.
Loam	Grows well here	Magnolia grows perfectly well on loam without special measures, though it is not the soil it would choose.
Silty	Grows well here	Magnolia grows perfectly well on silty without special measures, though it is not the soil it would choose.
Peaty and acid	Works, with one condition	Magnolia 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 rock	Works, with one condition	Magnolia will crop on shallow over rock, but one thing has to be dealt with first. It has little drought tolerance and this soil dries out fast — it will check and bolt in the first dry spell without watering.Water and mulch will carry it through. On this soil the watering is not optional in a dry spell, which is the difference between a crop and a failure.
Made ground and urban soil	Works, with one condition	Magnolia 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: 400–800 cm
Mature spread: 400–800 cm
Rooting depth: 80 cm
Spacing: 400–600 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: Magnolia — spacing
Checked 2026-08-13

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: Magnolia × soulangeana — foliage
Checked 2026-08-13
In a containerHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13

Growth rate: Slow — under about 30 cm a year
Ultimate height: 400–800 cm
Ultimate spread: 400–800 cm
Time to reach it: 25–40 yearsSourced guidance

Where these figures come from

Growth rateSourced guidancemoderate confidence: Royal Horticultural Society: Magnolia × soulangeana — growth rate
Checked 2026-08-13
Ultimate heightSourced guidancemoderate confidence: Royal Horticultural Society: Magnolia × soulangeana — ultimate height
Checked 2026-08-13
Ultimate spreadSourced guidancemoderate confidence: Royal Horticultural Society: Magnolia × soulangeana — ultimate spread
Checked 2026-08-13
Time to reach itSourced guidancelow confidence: Royal Horticultural Society: Magnolia × soulangeana — time to ultimate size
Checked 2026-08-13

Root space. Fleshy, brittle and close to the surface. It strongly resents being dug around or moved once established, and a magnolia that has been disturbed sulks for years rather than seasons.

source

Horticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

Cutting it back. Very little tolerance for it. Brittle wood that heals slowly, so prune in mid-summer, keep cuts small, and choose a plant sized for the space rather than planning to control it.

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.

Method	Suitability	What it needs
Open ground	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Traditional dug bed	Workable source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Raised bed	Marginal source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13	A raised bed rarely holds enough soil volume for a tree beyond its first few years.
Container	Marginal source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13

Growing it

PlantingAvoid an east-facing position and a frost pocket. The flowers open before the leaves and a single frost turns them brown overnight; morning sun on frosted petals does the same damage faster. A west-facing site with some shelter buys the display several extra days.
PruningPrune as little as you can, and in mid-summer when you must. Magnolias have brittle wood, heal slowly and resent hard cutting; the naturally spreading shape is the plant, and a magnolia pruned into a formal outline never looks right again.

Where this guidance comes from

PlantingSourced guidancehigh confidence: Royal Horticultural Society: Magnolia — position
Checked 2026-08-13
PruningSourced guidancemoderate confidence: Plant Finder — Missouri Botanical Garden: Magnolia — culture
Checked 2026-08-13

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.

If something is wrong with it

Flowers dropping without setting fruit — 2 causes GrowingHQ holds for magnolia

Something else? Work through it with the diagnostic tool.