Magnolia Grandiflora - Cultivation and Uses

Cultivation and Uses

The plant collector Mark Catesby, the first in North America, brought Magnolia 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).

Southern magnolia is a very popular ornamental tree throughout the southeastern United States and California, grown for its attractive shiny green leaves and fragrant flowers. It is also grown in Central and South America as well as parts of Asia.

It is often planted in university campuses and allowed to grow into a large tree, either with dependent branches, or with the lower branches removed to display the bare trunks. It is also espaliered against walls, which improves its frost-hardiness.

On the lower Ohio Valley, cold-hardy cultivars have been seen planted up to and even north of the Ohio River, where large tree specimens become increasingly rare and eventually are only found as shrubs before disappearing altogether from the landscape; for example, large mature trees are common in the Cincinnati, Ohio area but begin to taper off in size and occurrence until they are generally absent altogether in Cleveland, Ohio.

On the East Coast, this "subtropical indicator" tree is seen in some gardens in the Middle Atlantic States, including Delaware, New Jersey, southern Connecticut, far southeastern New York City suburbs/Long Island. Farther north in New England it is extremely difficult to cultivate, with few known long term specimens from Massachusetts northward to Canada. Towards the northern limit of its cultivation, it may suffer dieback from very hard freezes, but weathers normal freezes well. On the west coast it can be grown as far north as British Columbia/Seattle area, though cooler summers on the West Coast slow growth compared to the East Coast.

It is recommended for seashore plantings in areas that are windy but have little salt spray. The foliage will bronze, blotch, and burn in severe winters at the northern limits of cultivation, especially when grown in full winter sun but most leaves remain until they are replaced by new foliage in the spring. In climates where the ground freezes, winter sun appears to do more damage than the cold itself. In the northern hemisphere the south side of the tree will experience more leaf damage than the north side of the tree. Two extremes are known, with leaves white underneath and with leaves brown underneath. The brown varieties are claimed to be more cold-hardy than the white varieties, but this does not appear to be proven as yet. Once established plants are drought tolerant, and the most drought tolerant of all the Magnolia species.

The leaves are heavy and tend to fall year round from the interior of the crown and form a dense cover on top of the soil surface, 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.

In the United States, Southern magnolia along with sweetbay (Magnolia virginiana) and cucumbertree (Magnolia acuminata), is commercially harvested. Lumber from all three species is simply called magnolia, which is used in the construction of furniture, boxes, pallets, venetian blinds, sashes, doors and used as veneers. Southern magnolia has yellowish-white sapwood and light to dark brown heartwood that is tinted yellow or green. The usually straight grained wood has uniform texture with closely spaced rings. The wood is ranked moderate in heaviness, hardness and stiffness; moderately low in shrinkage, bending and compression strength; it is ranked moderately high in shock resistance. Its use in the southeastern United States has been supplanted by the availability of harder woods.

Symbolic of the American South, Magnolia grandiflora is the state tree of Mississippi, and the state flower of Mississippi and Louisiana. The flower was also used as an emblem of the Confederate army in the US civil war.