Southern Magnolia Magnolia grandiflora
Reviewed June 2026 · how we check this
A grand, broadleaf evergreen of the American South, prized for its glossy dark leaves with rusty-felted undersides and enormous, lemon-scented white flowers in early summer. Slow but stately, it becomes a long-lived landmark tree where it has room to spread.
Growing notes for · USDA Zone
Light
Southern magnolia flowers and fills out best in full sun — at least six hours a day — which yields the densest, most pyramidal crown and the heaviest bloom. It also tolerates partial shade, growing more open and flowering a little less freely beneath taller trees. Give it a wide, unobstructed site: this is a large evergreen that can reach 60–80 feet tall and 30–40 feet across, and its low, sweeping branches like to skirt the ground. Avoid crowding it against the house or under power lines. Young trees establish their framework best in an open, sunny spot with room to spread on every side.Watering
Newly planted southern magnolias need steady moisture to settle their coarse, fleshy, shallow roots — water deeply once or twice a week through the first two or three growing seasons, soaking the whole root zone, and more in heat or drought. A 2–3 inch ring of mulch (kept off the trunk) conserves moisture and protects those surface roots. The species naturally favors rich, moist bottomland soils and resents prolonged drought, which can trigger leaf drop. Once established it tolerates short dry spells but rewards an occasional deep soak in summer. Avoid waterlogged holes and standing water at the trunk, which rot the roots.Soil & potting
Southern magnolia thrives in deep, rich, moist but well-drained soil on the acidic side, ideally pH 5.0–6.5, generously supplied with organic matter. It naturally grows in loamy bottomlands and tolerates clay and brief flooding better than dry, compacted sites. In alkaline soils it often develops chlorosis, with yellowing leaves and green veins, so test before planting in lime-heavy regions and acidify if needed. Plant at the depth the tree grew in the nursery, keeping the root flare visible at the surface, and backfill with native soil rather than rich amendments. Its shallow roots resist competition, so keep turf and aggressive plantings back from the trunk.Humidity & temperature
Southern magnolia is hardy across USDA Zones 6–10, at home in the warm, humid summers of the American Southeast where its broadleaf evergreen canopy holds through winter. In Zone 6 and colder pockets, hard winters can brown or scorch foliage, so site it out of harsh, drying winter winds and choose a cold-hardy cultivar like 'Bracken's Brown Beauty' or 'Edith Bogue' near its northern limit. It relishes heat and humidity that would stress many trees. Give it good air circulation and a sheltered, sunny exposure, and established trees shrug off humidity and ordinary temperature swings with ease.Fertilizing
Established southern magnolias in decent soil seldom need feeding — a yearly topdressing of compost or organic mulch over the root zone supplies most of what they want and keeps the acidic, humus-rich conditions they prefer. For young trees or those with pale, sparse foliage, apply a balanced slow-release tree fertilizer in early spring as new growth begins, or one formulated for acid-loving plants. If leaves yellow between green veins on alkaline ground, the cause is usually micronutrient lockout rather than a shortage of fertilizer; correct it by acidifying the soil and supplying chelated iron. Avoid heavy nitrogen, which forces soft growth at the expense of flowers, and never feed a drought-stressed tree.Pruning & maintenance
Southern magnolia needs little pruning and is best left to keep its natural, low-skirted pyramidal form — those sweeping lower branches hide its leaf litter and are part of its beauty. Prune in late winter or early spring before new growth, removing only dead, damaged, or crossing branches and any competing leaders to maintain a single strong trunk. The tree heals slowly, so make clean cuts just outside the branch collar and avoid large wounds. If you must raise the canopy for clearance, do it gradually over several years. Resist heavy shearing; this is a tree to shape lightly when young, then leave alone.Propagation
Southern magnolia grows from seed, though slowly and with patience: collect the red, fleshy-coated seeds from the cone-like fruit in fall, clean off the pulp, and give them about three months of cold, moist stratification before sowing, as fresh seed loses viability if it dries out. Seedlings can take many years to flower. Named cultivars with superior form, bloom, or cold-hardiness are propagated by grafting or by rooting semi-hardwood cuttings under mist with rooting hormone, which is exacting and slow. Most gardeners simply plant a nursery-grown sapling, staking it loosely if needed and watering attentively through establishment for the surest start.Common problems
Through the year
Spring
Old evergreen leaves yellow and drop as fresh growth pushes out; mulch the root zone, water young trees, and do any light pruning before new growth hardens.
Summer
Peak season — huge fragrant white flowers open; keep young trees deeply watered through heat and drought, and enjoy the bloom.
Fall
Cone-like fruit ripens to reveal red seeds; collect seed if propagating, and keep watering until the ground cools.
Winter
Evergreen and resting — shelter young trees from drying winter winds near the cold limit, and protect thin bark from sunscald.
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