Tree or large shrub
How to grow magnolias
Magnolia × soulangeana / M. stellata
Choose a magnolia for the space you have, because it resents being moved or cut back later: Magnolia stellata stays under 3 m, Magnolia × soulangeana makes a tree 6 m or more across. Plant between October and March in sun or light shade, sheltered from wind and out of frost pockets, in moist, free-draining, neutral to acid soil. Keep the rootball level with the surface, mulch every spring, never dig over the shallow roots, and prune only in summer.
- Hardiness
- Fully hardy (flowers frost-prone)
- Position
- Full sun to light shade, sheltered
- Soil
- Humus-rich, moisture-retentive, free-draining, slightly acid to neutral
- Ideal pH
- 5.5 to 6.5
- Water
- Moderate, mulch to keep shallow roots moist
- Feeding
- Light feeder
Sowing and planting magnolias
WhenPlant Oct to Mar; flowers Mar to May; prune only in Jul to Aug if needed
Starting off
Plant pot-grown stock Oct to Mar, or Mar to Apr on heavy soil, choosing the site for good, as the fleshy roots resent moving; never dig around it once established. Propagate by 10 cm softwood cuttings in Jun with bottom heat at 20°C under mist, which is unreliable at home; layering a low branch in Apr and severing it after 2 years is the surest method. Grafted plants flower in 3 to 5 years; seedlings take 10 to 15.
Spacing and planting
M. × soulangeana reaches 6 to 8 m tall by 6 m wide in 20 years; M. stellata stays at 2.5 to 3 m by 3 m; M. 'Susan' and 'Leonard Messel' 4 m by 3 m. Plant 4 to 6 m from buildings and drains for the large types, in a hole three times the rootball width and no deeper, with the rootball top level with the surface. M. stellata and 'Susan' do well in a 60 cm pot for 5 to 8 years; M. × soulangeana is not a container plant.
Varieties worth growing
- M. stellata 'Royal Star'
- The star magnolia: white, many-petalled flowers in March and April on a slow, rounded shrub to about 2.5 m. Flowers from a young age and fits a small garden or large pot.
- M. × soulangeana
- The big goblet magnolia of front gardens, white flushed purple-pink in April. Needs a space at least 6 m across and tolerates clay and town air.
- M. 'Susan'
- Upright shrub to about 4 m with slim red-purple flowers in late April and May, late enough to miss most frosts.
- M. × loebneri 'Leonard Messel'
- Lilac-pink starry flowers on a small tree to 4 or 5 m; the flowers shrug off some frost and it is one of the best magnolias for alkaline soil.
- M. 'Black Tulip'
- Deep burgundy, tulip-shaped flowers in April on a narrow, upright small tree; a good choice where there is height but little width.
Magnolias month by month
Timings are for central England. Allow two weeks later in the north and on cold, heavy soil.
- January
Nothing to do. Plant in a mild spell if the ground is workable.
- February
Plant. Furry flower buds are swelling; do not prune.
- March
M. stellata flowers. Light feed for young trees. On heavy soil, plant now and in April.
- April
Main flowering. Fleece small plants on frost nights. Mulch 5 to 8 cm. Layer a low branch.
- May
'Susan' and other late kinds flower. Water new trees weekly.
- June
Water in dry spells. Softwood cuttings if you have a propagator.
- July
Pruning window opens: dead, damaged and crossing branches only.
- August
Finish any pruning. Water trees planted in the last two years.
- September
Next year's flower buds are visible. Nothing to do.
- October
Plant from now. Rake up spotted leaves.
- November
Plant. Remove rootstock suckers at the base.
- December
Nothing to do.
Feeding magnolias
A light feeder. Young trees get a half-rate balanced feed in March for their first few years; an established magnolia in decent soil needs only its yearly mulch. Heavy feeding gives leaf at the expense of flower.
Low, a light spring feed; mulch to keep the roots cool and moist.
Feeding plan
Planting
5 g per litre of rootball, dusted onto the roots or into the hole so it touches them: 50 g for a plant from a 10 litre pot. Once only.
March, the first 3 to 5 years
50 g/m², half the label rate, scattered under the canopy and watered in, not forked in: about 90 g for a young tree 1.5 m across (1.8 m²).
April, every year
Leaf mould or composted bark
A 5 to 8 cm mulch over the root area, kept off the trunk. For an established tree this is the whole feeding plan.
March, pots
2 g per litre of compost on the surface, the bottom of the label range, watered in: about 180 g for a 60 cm pot (about 90 litres).
May to July, after planting or a hard spring, every 3 weeks
1 g per litre of water, 10 litres drenched over the root area.
Signs to watch
Yellow leaves with green veins, especially on young growth → lime-induced chlorosis on chalk or shallow limestone → chelated iron, sulphur chips, a thick leaf-mould mulch; on thin chalk choose M. × loebneri 'Merrill' or 'Leonard Messel', which tolerate lime better. Few flowers on a leafy young tree → youth (3 to 5 years for grafted plants) or excess nitrogen → no feeding, sulphate of potash in Mar. O
Pests, diseases and problems
Open flowers and showing buds turn brown and limp overnight
Frost, worst where early sun strikes frozen petals
Plant away from frost pockets and east-facing sites, fleece small plants on frost nights, and choose later-flowering kinds such as 'Susan' in cold gardens. Buds still tight are usually unharmed.
Angular black or dark brown spots on the leaves in a cool, wet spring, sometimes with blackened shoot tips
Bacterial leaf spot
Cosmetic in most years. Rake up fallen leaves and cut out any blackened shoots in dry weather in summer.
White, waxy, cushion-like blobs on the trunk and branches in May and June
Horse chestnut scale, which also feeds on magnolia
Mostly harmless on a healthy tree. Brush egg masses off small trees with a stiff brush; mulch and water to keep the tree vigorous.
Coral-pink pustules on dead and dying twigs
Coral spot entering through dead wood, frost damage or pruning snags
Cut out affected wood to healthy tissue in summer and bin it. Never leave stubs.
Leaves and soft new shoots of a newly planted magnolia eaten ragged
Slugs and snails
Torch patrols in the first two springs and a clear, mulched circle round the stem. Established trees outgrow the damage.
Leaves small and sparse, branches die back, white fungal sheet under the bark at the base
Honey fungus
No cure. Remove the tree with as much root as possible and replant the site with something less susceptible.
Pruning
Pruning and care
Needs almost no pruning: remove dead, crossing or wind-damaged branches only, in Jul to Aug when the tree is in full leaf, since cuts in winter bleed and invite dieback, and never remove more than a fifth of the canopy in one year. Overgrown trees are reduced over 3 summers. Cut out suckers from the rootstock at the base. Mulch 5 to 8 cm with leaf mould or composted bark each Apr over the shallow roots,
Good to knowSite early-flowering types away from frost pockets and morning sun (frosted buds thaw too fast). Shallow-rooted, don't dig around it.
Growing magnolias in pots
Only the small magnolias suit a pot: M. stellata and 'Susan' will grow in a 60 cm container for five to eight years, while M. × soulangeana should go in the ground. Use a loam-based compost, ericaceous if your tap water is hard, and a heavy pot that will not blow over in leaf. Water steadily through summer, since a dry spell in July and August costs flower buds, and top-dress each March. Once the tree stops making good growth, plant it out; do not keep potting on.
Magnolias: common questions
When is the best time to plant a magnolia?
Between October and March, while the plant is dormant and the soil is not frozen. On heavy clay wait until March or April so the fleshy roots are not sitting in cold, wet ground all winter. Water through the first two summers.
Why is my magnolia not flowering?
Usually it is too young. Grafted magnolias take three to five years to settle and flower, and seedlings can take ten or more. Frost on the buds, winter pruning that removes them, dry roots the previous summer and heavy nitrogen feeding are the other causes.
Can I prune a magnolia to keep it small?
Only a little. Magnolias respond to hard pruning with thickets of upright shoots and few flowers, so remove no more than a fifth of the canopy in a year, in July or August, and spread any reduction over three summers. It is better to plant a small kind such as M. stellata.
Sources
Growing information on this page was checked against these references in November 2026. Feeding rates are Dr Forest label rates.