How to grow magnolias

What are magnolias?

Magnolias are popular ornamental trees or shrubs, widely grown in gardens and prized for their large showy flowers in spring and summer.

They are hardy, but prefer a sheltered spot and moist, well-drained soil. Some need slightly acidic or neutral conditions. Many magnolias are deciduous, losing their leaves over winter, but a few are evergreen, with dark glossy leaves all year round.
 

Choosing the right magnolia for you

 
When choosing a magnolia, it’s worth considering:

• Flower colour and flowering time

• Ultimate size of the plant

• Soil type

Flower choice

 
Most magnolias have either white or pink flowers, from rich magenta through soft rose to palest blush and snow white. There are a few maroon, dark purple, yellow or cream cultivars too. Flower size and shape can also vary, with star, bowl and goblet forms.
 
Magnolias can flower for a long period, often with a second flush a few months later. Different species bloom at different times, from early spring to late summer. If you live in a frost-prone region, it would be best to avoid early-flowering species, as the buds and flowers are easily browned by frost.
 

Plant size

Magnolias grow to a wide range of sizes, from shrubs just 1–2m (3¼–6½ft) tall to large trees. So it’s important to choose a plant to suit the amount of space you have available: 

• For a small space, consider a star magnolia (M. stellata or its cultivars), with many-petalled white or pale pink blooms. Compact magnolias will even grow well in large containers.

• For a medium-sized tree, perhaps as a specimen in a lawn, consider species such as M. × soulangeana, M. denudata and M. × loebneri.

• For growing against a large wall, consider an evergreen magnolia, such as M. grandiflora.

Soil type

 
Many magnolias prefer slightly acidic or neutral soil, although several (such as M. × loebneri, M. sieboldii and M. stellata) will cope in alkaline or chalky soils.

If your soil is very chalky, consider growing a compact magnolia in a container.

See our guide to identifying your soil type.

How and what to buy

Magnolias are available in garden centres, tree nurseries and from online suppliers, including RHS Plants. For the widest choice of cultivars, try a specialist tree supplier.
 
Plants are sold at a range of sizes, depending on price. Smaller plants tend to establish more quickly, but may take a few years to flower.

For tips on choosing a healthy specimen, see our video guide to tree buying. 
 

Where to get ideas and advice

To explore your potential planting choices, you can:

• Visit gardens that feature lots of magnolias and see which you like best. Many Cornish gardens are renowned for their magnolias, but you’ll also find them in gardens and arboreta across the country, including RHS Gardens.

• Ask at local garden centres, which should offer a range of magnolias that do well in your local conditions.

• Go to RHS Find a Plant. Search for ‘magnolia’ to browse the photos and plant descriptions, and find out where to buy them.

• Visit a specialist tree nursery, in person or online.
  

  

  How to boost soil acidity

  How to boost soil acidity

  

  Guide to planting under trees

  Guide to planting under trees

  Magnolias for small gardens

  Magnolias for small gardens

Where to plant

Magnolias are usually grown in the ground, but the compact forms can also be grown successfully in containers.

Most magnolias prefer:

• full sun
• fertile, moist, well-drained soil 
• ​slightly acidic or neutral conditions
• a sheltered position

Even if you don’t have these ideal conditions, you may still be able to grow selected magnolias. For example:

• Dry, alkaline soil – try Magnolia grandiflora or M. delavayi.

• Moist, alkaline soil – consider M. kobus, M. × loebneri, M. sieboldii, M. stellata and M. wilsonii.

• Wet soil – M. grandiflora and M. virginiana may be suitable.

• Light/dappled shade – choose from some of the later-flowering deciduous species, such as M. wilsonii and M. sieboldii. 

For more on assessing your conditions, see our guide to identifying your soil type and testing your soil pH.

Guide to chalky soil

Guide to chalky soil

• Frost can damage magnolia buds and flowers in spring and evergreen foliage in autumn.

• For shelter and protection, evergreen magnolias are often grown against a warm wall. See our guide to growing wall shrubs.

• Evergreen M. grandiflora and M. delavayi may not survive where the temperature drops below -5°C (23°F).

• M. grandiflora may need staking when planted in open ground, even when quite mature. See our guide to staking trees.   

• If you’re considering planting against a wall, it’s worth noting that reports of damage to buildings by magnolias are uncommon.

See our guide to assessing your microclimate.

Always consider the ultimate size of a tree before buying, to make sure it’s suitable for your garden. Some magnolia species can grow extremely large and need lots of space. However, there are plenty of more compact options that grow to only about 2m (6½ft), for less spacious sites. See our guide to magnolias for small gardens.  
 

When to plant

 
Magnolias are available to buy all year round, but are best planted between autumn and spring, whenever the ground isn’t frozen.
 

How to plant

Magnolias are easy to plant – see our guide to planting trees and shrubs.

Magnolias need little attention once they’ve settled in, as long as they’re growing in suitable conditions. However, when grown in containers, they need regular watering and feeding during the growing season.
 

Watering

Newly planted magnolias should be watered regularly for the first few years. Once well established, they may still need watering during dry spells or when growing in light, free-draining soil.
 
Magnolias growing against a wall may need additional watering, as they may be sheltered from rainfall.
 
If planted in a lawn, keep a circle of bare soil, at least 1.2m (4ft) in diameter, around the plant for at least the first few years. This helps rainwater to reach the roots, rather than being absorbed by the grass.
 
Plants in containers can dry out quickly, so should be watered regularly during the growing season.
 

Tips on recycling and collecting water

Tips on recycling and collecting water

How to water efficiently

How to water efficiently

Feeding

Newly planted magnolias are best fed annually for the first few years, to get them off to a good start. In late winter, scatter a general fertiliser around the base, at the rate recommended on the packet

After that, they generally don’t need feeding, unless the soil is very poor or growth and flowering need a boost.  see our guide to feeding plants.

Plants in containers have little access to nutrients, so need feeding regularly during the growing season. It is also best to topdress in spring – scrape off the top 5cm (2in) of compost and replace with fresh compost and a little slow-release fertiliser, such as Vitax Q4 or blood, fish and bone.

See our guide to container maintenance and growing trees in containers. 

Mulching

Mulch the root zone with a thick layer of organic matter such as garden compost every spring or autumn. This helps to hold moisture in the soil, so is especially important in a well-drained site.
 
Leave a 10cm (4in) collar free of mulch around the base of the stem, to avoid the risk of rotting the bark.
 

Caring for older plants

Magnolias can be long-lived trees, but may eventually start to decline – see our guide to looking after older trees.

If trees get too large or become lopsided, you can try renovative pruning – see Pruning and training below.

Deciduous magnolias

With magnolias that lose their leaves over winter, pruning is seldom required.

However, it may be necessary in a few circumstances:

• To keep trees healthy – remove any dead, damaged or diseased wood. See our guide to light pruning. 

• To reduce a tree’s size – aim to maintain an open, balanced crown by thinning out stems to the trunk or to a sideshoot. Stage the pruning over several years to avoid stressing the tree.

• To renovate an overgrown or misshapen tree – spread the pruning over two or three years. Trees may be slow to recover, and if they send up watershoots (vigorous vertical shoots) or stems die back after heavy pruning, remove these too.

• To shape trees after planting – remove weak and badly placed stems and shorten any long shoots.

Prune only between mid-summer and early autumn – cuts are liable to bleed sap if made in late winter or early spring. Always cut back to a natural fork, to avoid leaving unsightly stubs.

See our guide to pruning trees and shrubs.
 

Evergreen magnolias

With magnolias that keep their leaves all year round, little pruning is usually needed. It is only advisable:

• To keep trees healthy – remove any dead, damaged or diseased wood. See our guide to light pruning.

• To shape young trees after planting – simply shorten any lengthy young branches and, if you want a bare stem at the base, removal the lower boughs.

• To renovate misshapen or overgrown trees or to repair storm damage – hard pruning may be necessary. Cut back to the main framework or even beyond. It is safest to spread this work over several years.

Prune free-standing trees in spring, as growth begins, and wall-trained specimens (see below) in summer.

See our guide to pruning trees and evergreen shrubs.
 

Wall-training magnolias

Some evergreen magnolias, such as M. grandiflora, flower and grow particularly well if trained against a warm, sunny wall. To do this:

• Attach supports to the wall – such as a series of horizontal wires or trellis. Initially tie in the branches at a 45-degree angle, then lower to horizontal the following season. This encourages flowering and helps to spread the plant across the wall.

• In summer, remove any shoots growing towards the wall, and shorten outward-growing shoots to one or two leaves.

• If these outward-growing shoots bear flower buds, delay pruning until immediately after flowering.
  
  See our guide to pruning wall shrubs and initial training and pruning. 
  
  

  

  How to sharpen pruning tools

  How to sharpen pruning tools

You can use several methods to raise new magnolias from your original plant – layering is the easiest option, sowing seeds is fairly straightforward but quite slow, and taking cuttings can be a challenge:

• Layer shoots that are near ground level.

• Seeds – collect when the cones begin to split. The shiny black seeds have an orange-red fleshy covering. Wash this off, then place the seeds in a polythene bag of moist sand or vermiculite and refrigerate for two to four months. Sow into pots or trays of seed compost indoors. They should be ready to plant out in two or three years, but may not flower for 10 or more.

• Softwood and greenwood cuttings from deciduous magnolias – take in spring. Success rates can be low and artificial light may be needed from summer until leaf fall to ensure the cuttings have developed enough to survive the first winter. Apply liquid feed once rooted, and keep frost free over winter.

• Semi-ripe cuttings from evergreen magnolias – take in late summer or early autumn.

If planted in a sheltered spot, most magnolias grow and flower well with few problems. However, harsh weather and poor growing conditions can affect flowering and appearance. Look for:

• Lack of flowers – newly planted trees can take several years to settle in before they start flowering. Location can also affect flowering – M. grandiflora, for example, needs warm, sunny conditions. Hard pruning can also inhibit flowering.

• Blackened flowers or buds – frost damage often affects early-flowering magnolias.

• Yellow leaves – young leaves of many magnolias are naturally pale, but yellowing of more mature foliage may be caused by excessive alkalinity. See our guide to testing your soil.

• Brown leaves – may be caused by drought.

• Leaf loss – the leaves of evergreen magnolias are long lasting but are shed after several years, leading to harmless, if alarming, leaf fall episodes in early summer.

Several fungal diseases and rots can affect magnolias, including:

• bracket fungi

• honey fungus

• Phytophthora root rot