Magnolia grandiflora, commonly known as the southern magnolia or bull bay, is a tree of the family Magnoliaceae native to the Southeastern United States, from Virginia to central Florida, and west to East Texas. Reaching in height, it is a large, striking evergreen tree, with large, dark-green leaves up to long and wide, and large, white, fragrant flowers up to in diameter.

Although endemic to the evergreen lowland subtropical forests on the Gulf and South Atlantic coastal plain, M. grandiflora is widely cultivated in warmer areas around the world. The timber is hard and heavy, and has been used commercially to make furniture, pallets, and veneer.

Description

thumb|Flower and foliage of M. grandiflora

Magnolia grandiflora is a medium to large evergreen tree which may grow tall. It typically has a single stem (or trunk) and a pyramidal shape. The leaves are simple and broadly ovate, long and broad,

Pollination of the flower produces a rose-colored fruit, an ovoid polyfollicle that is approximately long and wide.

Taxonomy

M. grandiflora was one of the many species first described by Linnaeus in the 10th edition of his Systema Naturae in 1759, basing his description on the earlier notes of Miller. He did not select a type specimen. Its specific epithet is derived from the Latin words grandis "big", and flor- "flower". The genus name Magnolia honors Pierre Magnol, a French botanist. The timber is known simply as magnolia. In more sheltered habitats, it grows into a large tree, but can be a low shrub when found on coastal dunes.<!-- ref covers whole section currently --> It is killed by summer fires, and is missing from habitats that undergo regular burning.

In Florida, it is found in a number of different ecological areas that are typically shady and have well-draining soils; it is also found in hummocks, along ravines, on slopes, and in wooded floodplains. Despite preferring sites with increased moisture, it does not tolerate inundation.

Alongside a number of other magnolias, the southern magnolia has proven capable of surviving the cool winters of the British Isles, though growth is slow due to the lack of heat in summer. It was introduced to Great Britain in 1728, and has become a popular ornamental tree in some areas.

Ecology

thumb|Individual seeds

M. grandiflora can produce seed by 10 years of age, although peak seed production is achieved closer to 25 years of age. Around 50% of seeds can germinate, and they are spread by birds and mammals.

Cultivation and uses

Plant collector Mark Catesby, the first in North America, brought M. grandiflora to Britain in 1726, where it entered cultivation and overshadowed M. virginiana, which had been collected a few years earlier. It had also come to France, the French having collected it in the vicinity of the Mississippi River in Louisiana. It was glowingly described by Philip Miller in his 1731 work The Gardeners' Dictionary. One of the earliest people to cultivate it in Europe was Sir John Colliton of Exeter in Devon; scaffolding and tubs surrounded his tree, where gardeners propagated its branches by layering, the daughter plants initially selling for five guineas each (but later falling to half a guinea).

United States cultivation

M. grandiflora is a very popular ornamental tree throughout its native range in the coastal plain of the Gulf/South Atlantic states. Grown for its attractive, shiny green leaves and fragrant flowers, it has a long history in the Southern United States. Many large and very old specimens can be found in the subtropical port cities such as Houston; New Orleans; Mobile, Alabama; Jacksonville, Florida; Savannah, Georgia; Charleston, South Carolina; and Wilmington, North Carolina. M. grandiflora is the state tree of Mississippi and the state flower of Louisiana.

The species is also cultivated as far north as coastal areas of New Jersey, Connecticut, Long Island, New York, and Delaware, and in much of the Chesapeake Bay region in Maryland, and eastern Virginia. On the West Coast, it can be grown as far north as the Vancouver, British Columbia, Canada area, though cooler summers on the West Coast slow its growth compared to the East Coast.

M. grandiflora is also grown in parts of Mexico, Central America, and South America, as well as parts of Asia. It was reputedly planted as a seedling taken from Jackson's plantation, The Hermitage in Tennessee. It was the oldest tree on the White House grounds and was so famous that it was for decades pictured on the back of the $20 bill as part of a view of the South Front. There was a tradition of giving cuttings or seedlings grown from the tree: Reagan gave a cutting to his Chief of Staff Howard Baker upon his retirement, and Michelle Obama donated a seedling to the "people's garden" of the U.S. Department of Agriculture. at the place of the original tree. The foliage will bronze, blotch, and burn in severe winters at the northern limits of cultivation, especially when grown in full winter sun, and they have been used in decorative floral arrangements. The leaves have a waxy coating that makes them resistant to damage from salt and air pollution. Its use in the Southeastern United States has been supplanted by the availability of harder woods.

Cultivars

Over 150 cultivars have been developed and named, although only 30 to 40 of these still exist and still fewer are commercially propagated and sold. Most plants in nurseries are propagated by cuttings, resulting in more consistent form in the various varieties available. Some cultivars have been found to be more cold hardy, they include:

thumb|M. grandiflora 'Bracken's Brown Beauty' at the Morris Arboretum (Philadelphia, US)

  • 'Bracken's Brown Beauty' was developed by Ray Bracken of Easley, South Carolina, in the late 1960s and patented in 1985.
  • 'Exmouth' was developed in the early 18th century by John Colliton in Devon. It is notable for its huge flowers, with up to 20 petals, and vigorous growth. Erect in habit, it is often planted against walls. The leaves are green above and brownish underneath. The flowers are very fragrant and the leaves are narrow and leathery.
  • 'Goliath' was developed by Caledonia Nurseries of Guernsey, and has a bushier habit and globular flowers of up to diameter. Long-flowering, it has oval leaves which lack the brownish hair underneath.

Chemistry

Magnolia grandiflora contains phenolic constituents shown to possess significant antimicrobial activity. Magnolol, honokiol, and 3,5′-diallyl-2′-hydroxy-4-methoxybiphenyl exhibited significant activity against Gram-positive and acid-fast bacteria and fungi. The leaves contain coumarins and sesquiterpene lactones. The sesquiterpenes are known to be costunolide, parthenolide, costunolide diepoxide, santamarine, and reynosin.

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File:Magnolia grandiflora in Lakeland, Florida.jpg|Southern Magnolia in Lakeland, FL.

File:Magnolia grandiflora4.jpg|Bark on trunk

File:Southern Magnolia Leaf Cluster 3008px.jpg|A cluster of leaves

File:Magnolia tree mid-afternoon.JPG|From below

File:Southern magnolia -- Magnolia grandiflora bud.jpg|Southern magnolia bud

File:Magnolia grandiflora3.jpg|Southern magnolia foliage and flower

File:Southern magnolia -- Magnolia grandiflora.jpg|Southern magnolia blossom

File:2007 06 29 magnolia25.jpg|Inside the flower

File:2017-09-01 15 21 27 A Southern Magnolia blossom along Centreville Road (Virginia State Route 657) between Lees Corner Road and Franklin Farm Road in the Franklin Farm section of Oak Hill, Fairfax County, Virginia.jpg|Flower in three stages of blossoming

File:Magnoliatree.jpg|Seed cluster of M. grandiflora

File:Magnolia grandiflora, Montenegro.jpg|Mature fruit

File:Magnolia grandiflora 'Bracken's Brown Beauty' 08.jpg|Foliage 'Bracken's Brown Beauty'

File:Martin Johnson Heade - Magnolia.jpg|Martin Johnson Heade: Magnolia

File:Magnolia Hedge Dallas.jpg|A rare Magnolia hedge outside of the Nasher Sculpture Center.

File:MagnoliaIthaca.jpg|A hardy southern magnolia growing in Ithaca, NY.

File:Herbier Colorie de l'Amerique (44029724410).jpg|Illustration of plant

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References

Cited texts

  • United States Department of Agriculture Plants Profile for Magnolia grandiflora (southern magnolia)
  • Magnolia grandiflora images at bioimages.vanderbilt.edu