Tree · Magnoliaceae
Southern Magnolia
Magnolia grandiflora
A standout evergreen with glossy leaves and lemon-scented white blooms that anchors a landscape for generations.
Full sun
Every 7–14 days
USDA 6–10
60–80 ft · 18.3–24.4 m
Overview
Plant a southern magnolia and you plant the very tree that gives the American South its signature look. Give it time and it climbs to a commanding 60 to 80 feet (18 to 24 m), decked in thick, leathery leaves that gleam dark green up top and flash a rusty-brown felt beneath. Then late spring rolls in and the show begins: huge white flowers, each one cup-shaped and lemon-scented, throw their perfume clear across the yard.
Make no mistake, this tree thinks big and plays the long game, so hand it room to stretch. It piles on dense year-round shade and drives out wide, shallow surface roots, which team up to make growing grass beneath it a fight you will lose. It keeps dropping leathery leaves, spent flowers, and cone-like fruit almost all year, so steady litter comes with the package. Set it somewhere that shade and mess suit you, well clear of lawns and foundations, and you are off to a flying start.
Land the right spot and this tree practically grows itself. Feed it rich, moist, acidic soil and even water while it digs in, then watch it take over the job, brushing off serious pests apart from the odd bout of scale. Even better, newer cultivars have marched it well north of its old range, so cooler gardens can jump in and grow one too.
Care
The short version: hand it full sun to part shade and rich, evenly moist acidic soil, soak it deeply through dry spells while it is young, and barely touch the pruners beyond clearing dead or crossing wood.
Light
Southern magnolia truly comes alive in full sun, though it takes partial sun and partial shade in stride. Pour on the sun and you drive denser growth and a heavier burst of flowers; slide it into shade and you get a looser, more open tree. Both look great, so plant to the effect you want.
Water
Keep that soil consistently moist, and soak it deeply through dry spells, above all while the young tree digs in. Once it settles, a good drink every 7 to 14 days in dry weather keeps it cruising. Steer clear of both prolonged drought and standing water, because it shrugs off neither.
Soil
Set it into rich, organically rich, well-drained loam that holds its moisture. This tree runs acidic and hits its stride at a pH of 5.0 to 6.5; it will handle clay, but waterlogged or extreme ground drags it down, so give it something loose and lively.
Temperature
It powers through a wide swing, roughly -9°F to 100°F (-23°C to 38°C), which covers Zones 6 through 10. Perched at the cold northern edge? Reach for a hardy cultivar and grow with confidence.
Humidity
Everyday outdoor air does the job, so forget chasing a humidity number. Warm, muggy spells can kick off algal leaf spot, but it stays cosmetic and easy to shrug off.
Feeding
Feed it once in spring with a balanced or acid-forming slow-release fertilizer built for acid-loving trees. Keep it light, though, since a nitrogen overload pumps out soft growth that scale insects home right in on.
Pruning
Here is the fun part: this tree barely needs any pruning. Clear out dead, damaged, or crossing branches in late winter to early spring, and let the low limbs sweep the ground if you would rather they bury the leaf litter than bare the trunk.
Repotting
A tree in the ground never needs repotting, and even container stock moves only rarely. Spot an outgrown nursery plant by roots circling the rootball, roots bursting through the drainage holes, and water racing straight through instead of soaking in.
Size & spacing
Plan big, because this tree hits 60 to 80 feet (18 to 24 m) tall and 30 to 50 feet (9 to 15 m) wide. Hand it that whole footprint of open ground, clear of buildings and lawn, and let the canopy and surface roots really stretch out.
When to plant
This is a tree you plant for keeps, not a crop you race against the calendar. Get it in the ground in spring or fall while the weather stays mild and let it dig in. From there the dates worth circling are all about the payoff: those big white flowers burst open from late spring into summer, peak hard in May and June, then keep sprinkling on afterward.
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 thriving southern magnolia throws almost no curveballs, and the few it does show up right out on the twigs and leaves where you can pounce on them. Catch them early and you shut most of them down fast. Track down the symptom that matches yours below, then move before it spreads.
Whole branches wilting and dying back one at a time
When branches wilt and brown out one by one on their own, verticillium wilt is usually behind it, a soil fungus that clogs the wood from the inside. Slice the bark and you may catch dark streaks in the vascular tissue, but only a lab test nails it down. No chemical cure exists, so cut out the dead wood and drive the tree forward with steady water and feeding.
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 over a sticky, blackened film
Those raised, shell-like bumps are magnolia scale, one of the rare pests bold enough to bother this tree. The feeding scales drip honeydew, and black sooty mold piles onto it across the leaves below. Hit back: prune out the worst twigs, smother overwintering scale with horticultural oil in the dormant season, and knock down the crawlers in late summer.
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 on the leaves, sometimes with early leaf drop
Most leaf spots here run fungal or bacterial, and warm, humid weather can toss in the greenish-gray patches of algal leaf spot for good measure. None of it lands a lasting blow. Rake up and bin the fallen leaves, open the canopy with light pruning to get air moving, and skip the sprays, which rarely earn their keep.
Fix:
- Rake up and dispose of infected fallen leaves
- Improve air circulation by spacing and selective pruning
- Chemical control is rarely needed
Toxicity
Pet owners, breathe easy and dig in, because the southern magnolia is safe. The ASPCA lists magnolia as non-toxic to cats, dogs, and horses, and nothing in the tree poisons people, livestock, birds, or rabbits. Push it and the worst a big mouthful of leaves brings is a quick, mild stomach upset, the same as plenty of other plants.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
The ASPCA lists magnolia as non-toxic to cats, so wave off a nibbled leaf. A cat that really digs into the foliage might drool or throw up once, the way any rough plant material can jolt a stomach.
Dogs None
Dogs can chew the leaves with zero poisoning risk. The most a big mouthful throws at you is a quick bout of vomiting or a loose stool while the fibrous material runs through.
Horses None
Horses are in the clear too, magnolia sitting on the ASPCA non-toxic list. The tough, leathery leaves rarely tempt them anyway, and a stray mouthful does no harm.
Rabbits Safe
No toxin here comes anywhere near a rabbit. Their gut handles only small amounts of fresh greenery, so treat the odd leaf as a curiosity, not a meal.
Livestock Safe
Cattle, goats, and sheep can graze right up to a southern magnolia in safety, since nothing in the tree poisons them. They usually breeze past the stiff evergreen leaves anyway.
Birds Safe
The tree throws no chemical danger at birds, which pile into its dense canopy to shelter and nest. Some even peck at the bright red seeds in fall without a hitch.
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 reason 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 take the wild tree and sharpen it, swapping a bit of height for cold tolerance, smaller leaves, or a tighter shape. These are the ones to chase down.
Little Gem
A compact semi-dwarf that caps out near 30 feet with smaller leaves and flowers, kicks off blooming while still young, and slots right into a yard too small for the full-size tree.
Bracken's Brown Beauty
A cold-hardy, compact standout that powers through Zone 6, its smaller leaves backed by a thick, rusty-brown felt underneath.
Edith Bogue
One of the toughest picks for a brutal site, celebrated for shaking off cold, wind, and heavy snow.
D.D. Blanchard
A vigorous grower that rockets to about 75 feet on a straight trunk, flaunting dark glossy leaves over rich brown undersides.
How to propagate
Fancy making more? You can grow a southern magnolia from seed or clone one you already have, and every route rewards a patient hand. Your pick comes down to whether you want to lock in a specific cultivar's traits.
SeedModerate
Sow cleaned seed in fall or after cold stratification · Several months to germinate; years to reach flowering size
Peel off the red fleshy coat, then sow the cleaned seed in fall or run it through a cold spell first. Germination takes several months, and a seedling needs years to reach flowering size as it drives down a strong taproot, so settle in for the long haul. Seed will not copy a named cultivar, so grab this route only when you welcome whatever pops up.
Air layeringModerate
Spring to summer on actively growing wood · Several months to root
Air-layering is the most reliable way to clone a southern magnolia and lock in its cultivar traits. Work actively growing wood from spring through summer, and give it several months to root before you cut the new plant loose.
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 park them under mist. Rooting crawls along here, slow and uneven, from several weeks to a few months, which is exactly why it tests your patience.
GraftingDemanding
Late winter to spring · One or more seasons to unite
Graft from late winter into spring to fuse a named cultivar onto seedling rootstock and carry the parent's traits forward. The union needs one or more seasons to knit tight, and the technique demands a skilled hand, so it is a rewarding one to master.
Myths
Southern magnolia is poisonous to dogs and cats.
Toss that worry out, because the ASPCA lists magnolia as non-toxic to dogs, cats, and horses, so a curious pet that chews a leaf faces zero danger. Push it and you get at most a quick, mild stomach upset, the same thing any plant material can spark. Plant it around pets and enjoy it.