Southern magnolia (Magnolia grandiflora): what the agencies record

This page reports what US federal publications say about one tree. It does not identify trees from descriptions or photos and does not say what should be done with any tree. The family overview, tree species in the agency records, explains the sources and holds the comparison table.

At a glance

Item	What the source records
Scientific name	Magnolia grandiflora L., magnolia family (Silvics)
Other names	Evergreen magnolia, bull-bay, big-laurel and large-flower magnolia (Silvics)
Native status, USDA PLANTS	Native in the lower 48 states; introduced in Puerto Rico
Size, Silvics	On good sites average 18 to 24 m (60 to 80 ft) tall and 61 to 91 cm (24 to 36 in) in diameter in 80 to 120 years; 30 to 38 m (100 to 125 ft) reported in Florida
Green weight of the wood, NRS-38	59 lb per cubic foot, without bark

Native range and where it grows

The Silvics of North America handbook (Agriculture Handbook 654, 1990) gives a range from eastern North Carolina south along the Atlantic Coast to the Peace River in central Florida, then west through roughly the southern half of Georgia, Alabama and Mississippi and across Louisiana into southeast Texas. It says the tree is most prevalent in Louisiana, Mississippi and Texas. No part of the natural range is higher than 150 m (500 ft) in elevation. The handbook describes a moderately fast-growing, medium-sized tree that grows best on rich, moist, well-drained soils of the bottoms and low uplands of the Coastal Plain, in warm temperate to semitropical climates with a frost-free period of at least 210 days.

Silvics says southern magnolia grows best on rich, loamy, moist soils along streams and near swamps and also on mesic upland sites where fire is rare. It cannot withstand prolonged inundation, so it does not appear in the first bottoms. It rarely forms pure stands and is a minor part of six forest cover types, among them Southern Redcedar, Cabbage Palmetto, Loblolly Pine-Hardwood and Live Oak.

Flowers and fruit

The handbook says the large, white, fragrant flowers are perfect and appear from April to June. The fleshy cone-like fruit matures from September through the late fall, and when it opens the seeds, 6 to 13 mm (0.25 to 0.5 in) long, hang for a time on slender silken threads before dropping. Trees as young as 10 years can produce seed, with optimum production usually not until age 25, and good crops normally occur every year. The seeds are spread mostly by birds and mammals, and Silvics says seeds rarely germinate under the parent tree because of reported inhibiting effects. It lists squirrels, opossums, quail and turkey among the animals that eat them.

Growth, shade, roots and fire

Silvics says the tree is overall tolerant of shade, endures considerable shade early in life and needs more light as it gets older, and many trees spend 10 to 20 years in the understory before reaching the upper canopy. It is described as a deep-rooted species except on sites with a high water table, with a taproot in seedlings and a heart root system later. Older trees may have a fluted base. Mature trees commonly send up root and stump sprouts. The handbook says seedlings are very susceptible to frost damage and are easily killed by fire, while older trees are quite fire resistant because of bark characteristics and sprout vigorously even if the top is killed. It calls southern magnolia one of the major species of the potential climax forest of the southeastern Coastal Plain.

Wood and uses

The Wood Handbook (FPL-GTR-282, 2021) says commercial magnolia lumber is sold from three species, southern magnolia, sweetbay and cucumbertree, under one name, and that Louisiana leads production. Sapwood of southern magnolia is yellowish white and the heartwood light to dark brown with a tinge of yellow or green. The wood has close, uniform texture, is generally straight grained and closely resembles yellow-poplar, and is moderately heavy, moderately low in shrinkage and in bending and compressive strength, moderately hard and stiff and moderately high in shock resistance. It names furniture, boxes, pallets, venetian blinds, sashes, doors, veneer and millwork. Silvics adds that florists prize the leathery foliage and that the tree is a valuable, extensively planted ornamental that grows in urban areas where other species do poorly because of its resistance to damage by sulfur dioxide.

Wood Handbook figure	Green	At 12% moisture content
Specific gravity (Table 5-3b)	0.46	0.50
Modulus of rupture, lbf per square inch (Table 5-3b)	6,800	11,200
Side hardness, lbf (Table 5-3b)	740	1,020

The green weight is in the NRS-38 table, the same figure used in the log weight calculator.

Damaging agents the handbook names

Fire and drought. Young trees are susceptible to fire-caused injury and death, and winter droughts can cause extensive dieback and death.
Scale insects. Heavy infestations of magnolia scale can kill branches or entire trees. Oleander pit scale and tuliptree scale attack and injure the tree but rarely kill it. The magnolia scale page sets out what extension services record for that insect.
Other insects. The tuliptree aphid, striped mealybug, a leaf weevil, the magnolia leafminer and a spider mite feed on it, and a wood borer can injure or kill nursery seedlings.
Diseases. Several fungi cause leaf spots that Silvics says seldom result in significant damage, though one can be a problem on nursery seedlings. Fomes and Polyporus fungi can cause heartrot.

For who takes reports of regulated pests, see reporting a pest in the United States, and pests and diseases by country sets out which ones agencies regulate.