Magnolia grandiflora

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.^[5] Reaching 27.5 m (90 ft) in height, it is a large, striking evergreen tree, with large, dark-green leaves up to 20 cm (7+3⁄4 in) long and 12 cm (4+3⁄4 in) wide, and large, white, fragrant flowers up to 30 cm (12 in) 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.

Distribution and habitat[edit]

Southern magnolias are native to the Southeastern United States, from Virginia south to central Florida, and then west to East Texas. The tree is found on the edges of bodies of water and swamps, in association with sweetgum (Liquidambar styraciflua), water oak (Quercus nigra), and black tupelo (Nyssa sylvatica). In more sheltered habitats, it grows into a large tree, but can be a low shrub when found on coastal dunes.^[13] It is killed by summer fires, and is missing from habitats that undergo regular burning.^[14]

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.^[15] Despite preferring sites with increased moisture, it does not tolerate inundation.^[9] It grows on sandhills in maritime forests, where it is found growing with live oaks and saw palmetto (Serenoa repens).^[14] In the eastern United States, it has become an escapee, and has become naturalized in the tidewater area of Virginia and locally in other areas outside of its historically natural range.^[16]^[17]

Alongside a number of other magnolias, the southern magnolia has proven capable of surviving the cool winters of the British Isles. It was introduced to Great Britain in 1728,^[18] and, as well as being a popular ornamental plant, has become naturalised.^[19]

'Bracken's Brown Beauty' was developed by Ray Bracken of Easley, South Carolina, in the late 1960s and patented in 1985. It is a popular cultivar that has survived long-term in West Virginia, New Jersey, and Long Island, NY. This cultivar grows in a dense and compact pattern, with narrow, medium-sized, glossy leaves. Flowers measure 5–6 in (13–15 cm).

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'Edith Bogue' was brought to the coastal plain of New Jersey from Florida in the 1920s. The original tree sent to Edith A. Bogue from Florida helped to establish cold-hardy specimens in the Middle Atlantic states from Delaware to coastal Connecticut. Once established, 'Edith Bogue' has been known to have only minor spotting and margin burn on the leaf in temperatures as low as −5 °F (−21 °C). With a vigorous classic pyramidal shape, this cultivar grows to 35 ft with a 15-ft spread. The leaves are large and deep green, but lack the brown on their undersides which make other cultivars so distinctive.

indumentum

'Angustifolia', developed in France in 1825, has narrow, spear-shaped leaves 20 cm (7.9 in) long by 11 cm (4.3 in) wide, as its name suggests.

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'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.^[37]

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'Goliath' was developed by Caledonia Nurseries of Guernsey, and has a bushier habit and globular flowers of up to 30 cm (12 in) diameter. Long-flowering, it has oval leaves which lack the brownish hair underneath.

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'Little Gem', a dwarf cultivar, is grown in more moderate climates, roughly from New Jersey, Maryland and the Virginias southward. Originally developed in 1952 by Steed's Nursery in , it is a slower-growing form with a columnar shape which reaches around 4.25 m (13.9 ft) high and 1.2 m (3.9 ft) wide. Flowering heavily over an extended period in warmer climate, it bears medium-sized, cup-shaped flowers, and has elliptic leaves 12.5 cm (4.9 in) long by 5 cm (2.0 in) wide.^[36] It flowers relatively quickly after planting compared with other cultivars.^[38]

Candor, North Carolina

"Victoria" is a form grown in the Pacific Northwest that is reportedly hardy to -12 F. It has a more open habit and shiny dark green leaves with brown undersides.

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Chemistry[edit]

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.^[39] The leaves contain coumarins and sesquiterpene lactones.^[40] The sesquiterpenes are known to be costunolide, parthenolide, costunolide diepoxide, santamarine, and reynosin.^[41]