Tree · Magnoliaceae
Southern Magnolia
Magnolia grandiflora
A grand evergreen whose glossy leaves and lemon-scented white blooms give a property its sense of permanence.
Full sun
Every 7–14 days
USDA 6–10
60–80 ft · 18.3–24.4 m
Overview
Few trees set a scene the way the southern magnolia does, which is why it reads as shorthand for the gracious American South. Given decades it becomes the anchor of a whole property, a stately evergreen of 60 to 80 feet (18 to 24 m) that holds its leaves the year round. From late spring into summer it opens huge cup-shaped, lemon-scented white flowers, and their perfume drifting across a yard can turn an ordinary afternoon into an occasion.
This is a tree that commands a setting rather than fits into one, so it belongs on a property with room to spare. Its dense, year-round shade and wide, shallow surface roots make the ground beneath it a place for a bench or a bed of mulch, not a lawn. It also keeps up a slow, steady drop of leaves, spent flowers, and cone-like fruit through the seasons, so plan for it well away from patios, walkways, and foundations where the litter would intrude on daily life.
Sited thoughtfully, it fits quietly into the rhythm of a garden and asks little in return. It wants rich, moist, acidic soil and steady water while it settles, then carries on largely by itself, rarely troubled by pests beyond the occasional scale. Newer cultivars have carried its Southern character into cooler regions, so gardens once considered too far north can now claim one of their own.
Care
The short version: set it in full sun to part shade and rich, evenly moist acidic soil, water deeply through dry spells while it is young, and keep pruning to little more than the odd dead or crossing branch.
Light
Southern magnolia looks its best in full sun, though it accepts partial sun and partial shade with ease. A sunnier position gives you a fuller, more flower-laden tree, the kind that reads as a centerpiece, while a shadier one produces a looser, more open shape that suits a woodland edge.
Water
Keep the soil consistently moist, watering deeply through dry spells and especially while the young tree finds its place. Once established, a deep soak every 7 to 14 days in dry weather keeps it content. It has no patience for prolonged drought or standing water, so even moisture is what keeps it looking its part.
Soil
Give it rich, well-drained loam with plenty of organic matter and a lasting bit of moisture. The tree favors acidic ground, at ease around a pH of 5.0 to 6.5; it will tolerate clay, but waterlogged or extreme soil undermines the poise it is prized for.
Temperature
It takes a wide range in stride, from about -9°F to 100°F (-23°C to 38°C), which covers Zones 6 through 10. For a garden near the cold northern edge, a hardy cultivar is the confident choice that keeps its winter looks intact.
Humidity
Everyday outdoor air suits it, so humidity is nothing to manage. Warm, muggy stretches can invite algal leaf spot, but the blemish is cosmetic and easy to overlook from across a garden.
Feeding
One spring feeding is enough, using a balanced or acid-forming slow-release fertilizer made for acid-loving trees. Keep it restrained, since too much nitrogen pushes soft growth that draws in scale insects and undoes the effortless look you are after.
Pruning
This tree needs little pruning to hold its form. Take out dead, damaged, or crossing branches in late winter to early spring, and consider leaving the low limbs to sweep the ground, a graceful skirt that hides fallen leaves rather than baring the trunk.
Repotting
In the ground it never needs repotting, and even a container specimen is moved only rarely. Before planting, look over a nursery tree for roots circling the rootball, roots slipping through the drainage holes, and water running straight through, all cues that it has outgrown its pot.
Size & spacing
Design around a large tree, 60 to 80 feet (18 to 24 m) tall and 30 to 50 feet (9 to 15 m) wide. Grant it that generous footprint, clear of buildings and lawn, so its canopy can spread and its surface roots have somewhere to go without crowding the rest of the garden.
When to plant
This is a tree you commit to a place, not a crop you schedule around a harvest. Plant it in spring or fall, while mild weather eases it into its new home. From then on the season worth marking is its flowering, the grand white blooms that open from late spring into summer, at their fullest in May and June before tapering off.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring or fall
- Harvest: Late spring to summer (May to June, with sparse continued flowering through summer)
Hardiness
USDA hardiness zones: 6–10
Temperature: down to -23°C
Troubleshooting
A well-placed southern magnolia settles into a landscape with little fuss, and the few problems it meets tend to surface on the twigs and leaves. Noticed early, most are a minor interruption rather than a real setback. Match what you see below and address it before it takes hold.
Whole branches wilting and dying back one at a time
When individual branches wilt and brown on their own, the usual cause is verticillium wilt, a soil fungus that quietly blocks the wood from within. A cut through the bark can reveal dark streaks in the tissue, though only a lab test settles it for certain. There is no chemical cure, so prune away the dead wood and keep the tree strong with steady water and feeding to preserve its stature.
Fix:
- Prune out and destroy affected dead branches
- Fertilize and water during dry weather to support recovery
- There is no chemical cure; keep the tree vigorous
Waxy white bumps on the twigs with a sooty film on the leaves below
The raised, shell-like bumps are magnolia scale, among the very few pests that disturb this otherwise composed tree. The scales feed and drip honeydew, and a black sooty mold settles onto it across the leaves beneath, dulling the polished look. Prune out the worst twigs, treat overwintering scale with horticultural oil in the dormant season, and address the crawlers in late summer to restore its shine.
Fix:
- Prune out and destroy heavily infested twigs
- Apply horticultural oil during the dormant season to smother overwintering scale
- Treat crawlers in late summer when young scales are active
Spots and blotches across the leaves, with a little early leaf drop
Most of the leaf spotting here is fungal or bacterial, joined in warm, humid weather by the greenish-gray patches of algal leaf spot. None of it does lasting harm to the tree's presence in a garden. Rake up and remove the fallen leaves, open the canopy with light pruning so air moves freely, and set the sprays aside, since they rarely earn their place.
Fix:
- Rake up and dispose of infected fallen leaves
- Improve air circulation by spacing and selective pruning
- Chemical control is rarely needed
Toxicity
For a household that shares its grounds with animals, the southern magnolia is safe company. The ASPCA lists magnolia as non-toxic to cats, dogs, and horses, and nothing in the tree threatens people, livestock, birds, or rabbits. The most a big mouthful of leaves might bring is a brief, mild spell of stomach upset, no different from many garden plants.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
The ASPCA lists magnolia as non-toxic to cats, so a nibbled leaf is nothing to fret over. A cat that overindulges on foliage might drool or bring it back up once, the way any coarse plant material can briefly unsettle a stomach.
Dogs None
Dogs can chew the leaves with no poisoning risk. The most a large mouthful is likely to bring is a passing bout of vomiting or a loose stool as the fibrous material moves through.
Horses None
Horses are equally in the clear, magnolia sitting on the ASPCA non-toxic list. The tough, leathery leaves hold little appeal as browse, and a stray mouthful does no harm.
Rabbits Safe
Nothing in the tree threatens a rabbit. Their systems handle only small amounts of new greenery, so an occasional leaf is best regarded as a curiosity rather than a staple.
Livestock Safe
Cattle, goats, and sheep may graze near a southern magnolia in safety, since nothing in it is poisonous to them. They tend to pass over the stiff evergreen leaves in any case.
Birds Safe
The tree holds no chemical danger for birds, which readily shelter and nest within its dense canopy. Some will sample the bright red seeds in fall without any trouble.
People Safe
Southern magnolia is not poisonous to people, and no part is known to harm anyone who handles it. The leaves and flowers are not food, though, so there is no call to eat them.
As with any plant, ingestion of plant material may cause mild, transient gastrointestinal upset even though the plant is non-toxic.
Varieties
Several named selections reinterpret the classic tree for different settings, trading some height for cold tolerance, smaller leaves, or a more contained silhouette. These are the ones worth considering.
Little Gem
A compact semi-dwarf that settles near 30 feet with smaller leaves and flowers, blooms while still young, and suits a courtyard or town garden too small for the full-size tree.
Bracken's Brown Beauty
A cold-hardy, compact selection that stands up to Zone 6, with smaller leaves lined beneath in a warm, rusty-brown felt.
Edith Bogue
One of the most dependable choices for an exposed site, admired for taking cold, wind, and heavy snow in stride.
D.D. Blanchard
A vigorous selection that rises to about 75 feet on a straight, elegant trunk, its dark glossy leaves set off by rich brown undersides.
How to propagate
A southern magnolia can be grown from seed or cloned from a tree already in the ground, though each approach rewards a patient gardener. The right choice comes down to whether keeping a particular cultivar's character matters to you.
SeedModerate
Sow cleaned seed in fall or after cold stratification · Several months to germinate; years to reach flowering size
Clear away the red fleshy coat, then sow the cleaned seed in fall or give it a cold spell first. Germination unfolds over several months, and a seedling takes years to reach flowering size as it establishes a strong taproot. Seed will not preserve a named cultivar, so reserve it for a spot where whatever emerges is welcome.
Air layeringModerate
Spring to summer on actively growing wood · Several months to root
Air-layering is the most dependable way to clone a southern magnolia while keeping a cultivar's character intact. Work on actively growing wood from spring through summer, allowing several months for roots to form before the new plant is separated.
Stem cuttingsDemanding
Semi-hardwood cuttings in summer · Several weeks to months under mist
Take semi-hardwood cuttings in summer, dip them in rooting hormone, and hold them under mist. Rooting comes slowly and unevenly here, over several weeks to a few months, which makes this the method that asks the most patience.
GraftingDemanding
Late winter to spring · One or more seasons to unite
Grafting from late winter into spring joins a named cultivar onto seedling rootstock so the new tree carries its parent's traits. The union needs one or more seasons to knit firmly, and the work calls for a practiced hand.
Myths
Southern magnolia is poisonous to dogs and cats.
The reassurance is on record: the ASPCA lists magnolia as non-toxic to dogs, cats, and horses, so a curious pet that chews a leaf comes to no harm. The most that might follow is a brief, mild spell of stomach upset, the same as with countless other plants. It belongs in a garden shared with pets.