Southern Magnolia

Magnolia grandiflora L.

Description

Southern magnolia is a broadleaf evergreen member of the magnolia family (Magnoliaceae).  Other names include evergreen magnolia, big-laurel, and large-flower magnolia.³  It has a pyramidal to rounded growth form and reaches a height of  80 feet.¹  The bark is typically gray to brown and smooth when young but becoming scaly with maturity.⁶  The 10-inch, elliptical alternate leaves are thick and leathery.⁶  Leaves have entire margins, are glossy dark green above, and are pale green to brownish below.⁶ The leaves may stay on the tree for up to two years. ⁶ The flowers are up to 12 inches in diameter,  white with 6 to 15 petals 6 and very fragrant. ²  The 3 to 5-inch fruit is cone shaped and produces bright red seeds attached with a thin thread. ¹  Seed production can occur in trees as young as 10 years.⁴

Mature trunk of southern magnolia.  J. Power, CalPhoto ⁸

Flower and leaves of southern magnolia. N. Kurzenko, CalPhoto ⁸

Fruit and seeds of southern Magnolia.  Z. Akulova, CalPhoto ⁸

Distribution

The historical range of southern magnolia is from North Carolina around the Gulf Coast to Texas.²  Elevations of less than 500 feet was typical for its original distribution. ³  However, it has escaped from cultivation and is now listed as far north as Pennsylvania and Kentucky.³    Susceptibility of seedlings to frost damage limits its spread.⁸   Mature trees ares  susceptible to winter dieback with temperatures below 15 °F or to periods of winter drought. ³  Southern magnolia is considered native to Maryland⁸, and has been recorded in the counties of the Eastern and Western Shores of the Chesapeake Bay.⁸

Historical distribution of southern magnolia.  Wikipedia⁸

Wildlife Importance

Seeds are eaten by squirrels, chipmunks, opossum, quail and wild turkey.⁸  The have a high fat content and make them a valuable food source for migratory birds such as wood thrushes, eastern kingbirds and red-eyed vireos.⁶

Economic Importance

The wood is hard and used to make veneer, crates, paneling, furniture  and pallets.⁸ It is widely planted as an ornamental.⁶

Threats

Young trees are susceptible to fire, but mature trees are more resistant³  While a number of fungi and insects may cause damage³, southern magnolia is considered to be relatively free of serious problems¹.

Interesting Facts

• ‘Braken’s Brown Beauty’ is a widely used cultivar that is more resistant to winter cold. ¹
• Roots can extend beyond the canopy by four times its width.⁶
• Southern magnolia is considered one of the most wind resistant trees and is suggested as a replacement for Bradford pear and silver maple.⁶
• The long-lasting leaves are popular for holiday decorations.⁶
• Maryland state champion southern magnolia is 65.9 inches in diameter and 72 feet tall found in Somerset County. It may date back to 1860.°

References

1. Magnolia grandiflora:  Missouri Botanical Garden
2. Magnolia grandiflora:  North Carolina State Extension
3. Souther Magnolia:  USDA Forest Service, Silvics Vol. 2. hardwoods
4. Magnolia grandiflora:  USDS Plants Database
5. Magnolia grandiflora:  USDA Fire Effects Information System
6. Southern Magnolia:  USDA Plant Guide
7. USDA map of Magnolia grandiflora: Wikipedia
8. Magnolia grandiflora: CalPhoto
9. Maryland Big Tree Program
10. Southern Magnolia:  Maryland Biodiversity Program

Contributed by J. Hull

Glen Arboretum at Towson University