Southern magnolia

Sun

Full sun to partial shade; flowering is best in sun. In cooler climates, choose a warm position sheltered from cold, drying winds.

Water

Water deeply during establishment and prolonged dry spells. Established trees tolerate some drought, but grow best with consistent moisture and good drainage.

Soil

Deep, fertile, moisture-retentive but well-drained soil, preferably acidic to neutral. Avoid waterlogged ground and strongly alkaline soil.

Height

60-80 ft (18-24 m)

Spread

30-50 ft (9-15 m)

Flowers

Large, fragrant, creamy-white flowers from late spring through summer, sometimes continuing into early autumn. Flowering is often later and less abundant in cool climates.

Foliage

Evergreen. Large, leathery, glossy dark-green leaves, often with rusty-brown felt beneath. Older leaves fall throughout the year, especially in spring.

Growth

Moderate; slower in cool climates or dry soil.

Care needed

Medium

• Plant with the root flare at soil level; allow room for the full-sized crown rather than relying on repeated pruning.
• Water the root area deeply during dry weather for the first two or three growing seasons.
• Maintain a 2-3 in (5-8 cm) mulch layer over the root area, keeping it clear of the trunk.
• Feed in spring only if growth is poor or a soil test shows a deficiency; avoid heavy nitrogen feeding.
• Avoid digging, compacting soil or laying paving over the shallow roots; stake only if the root ball moves in wind.

Pruning. Prune sparingly after the main flowering period, removing dead, damaged or crossing branches and making only small shaping cuts. Retain lower branches where space allows; avoid topping or severe crown reduction.

Early spring

In colder areas, plant once the soil is workable and no longer waterlogged.

Spring

Refresh mulch and check leaves for persistent yellowing that may indicate unsuitable soil or poor drainage.

Late spring

Check young trees for loose ties and remove stakes once the roots hold the tree firmly.

Summer

Water young trees during dry spells and lightly prune after the main flush of flowers if needed.

Autumn

Plant in mild climates while the soil is warm, and clear fallen leaves from paths and drains.

Winter

Check young trees for wind damage; water during dry periods only when the ground is unfrozen.

• Use as a specimen in a large lawn, with a broad mulched area beneath the crown.
• Retain branches to ground level to create a dense evergreen screen on a spacious boundary.
• Place behind camellias, azaleas and shade-tolerant groundcovers for a layered, acid-soil planting.
• Use beside a large terrace or entrance to provide year-round structure and summer fragrance, allowing clearance from paving and buildings.

Garden styles it suits: Southern, Traditional, Grand estate, Architectural minimal, Sensory garden and White garden.

Plant it with: Camellia, Azalea, Cast iron plant, Mondo grass and Christmas fern.

Wildlife: Flowers support beetles and other visiting insects. Birds and small mammals eat the red-coated seeds, while the dense evergreen canopy provides shelter and nesting cover.

• Yellow leaves with green veins: often caused by alkaline soil or impaired roots. Test soil pH, improve drainage where possible and use chelated iron as a temporary treatment if iron deficiency is confirmed.
• Magnolia scale and sooty mould: inspect twigs for scale insects and sticky honeydew. Use horticultural oil at the locally recommended stage, following the label, and avoid spraying during heat or drought stress.
• Root rot and decline: waterlogged soil can damage roots and encourage disease. Correct drainage, reduce unnecessary watering and keep mulch away from the trunk.
• Winter leaf scorch: cold, drying winds can brown foliage, especially on young trees. Provide shelter, maintain mulch and water before freezing weather if the soil is dry.

Not known to be toxic to cats, dogs, horses or people. Leaves, flowers and seeds are not normally considered poisonous, but the tough leaves and woody fruit are not suitable food and may cause digestive upset if eaten.

• Sweetbay magnolia (Magnolia virginiana)

  Usually smaller, with thinner leaves that are silvery beneath and much smaller cream flowers; it may lose its leaves in cold climates.

• Port wine magnolia (Magnolia figo)

  Usually a shrub with smaller leaves and small cream flowers, often edged in purple, with a strong banana-like scent.

• Bull bay 'Little Gem' (Magnolia grandiflora 'Little Gem')

  A cultivar of the same species, with smaller leaves and a narrower, slower-growing habit; it still becomes a substantial tree rather than remaining a small shrub.

Magnolia honours the French botanist Pierre Magnol, grandiflora means large-flowered, and southern refers to the tree's native range in the southeastern United States.

Propagation. Sow cleaned, fresh seed after a period of cold, moist stratification; seedlings vary and may take many years to flower. Named cultivars are usually propagated by cuttings or grafting to preserve their characteristics.

Accepted botanical name

Magnolia grandiflora

In the US and Canada

Native in the lower 48 states. Introduced in Puerto Rico.

Native range

Alabama, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina and Texas.

Measured

Soil pH 4.5 to 6.5. Average height 2450 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.