Plant of the Week: Magnolia Grandiflora

By Davis Landscape Architecture @DavisLandArch

Magnolia grandiflora flower (29/06/2011, London)

Position: Full sun to partial shade

Soil: Moist, well drained soil

Flowering period: Summer to early autumn

Eventual Height: 10m

Eventual Spread: 10m

Hardiness: USDA Zone 6a-10b

Family: Magnoliaceae

Magnolia grandiflora is an evergreen tree with a broadly conical or rounded habit that may become more open as the plant matures. It has large oblong, glossy, mid to dark green leaves that will fall year-round from the centre of the crown to create a dense leaf covering on the ground below the plant. It bears large, monoecious, bowl shaped, white flowers intermittently from mid summer to early autumn usually after the plant has achieved twelve years of ag..

Charles Plumier (1646-1704), unaware of any Asian names for the species, described a flowering tree from the island of Martinique as Magnolia in 1703. He named it after Pierre Magnol, a 17th century French botanist and this was later adopted by Linnaeus in the first edition of Species plantarum. grandiflora is derived from the Latin and is taken to mean ‘with large flowers’.

M. grandiflora, commonly known as the bull bay is native to south-eastern North America. In some parts of England its flowers are pickled and eaten for their spicy flavour and its bark has been used to treat malaria and rheumatism. It was introduced to Britain by Mark Catesby in 1726. 

Magnolia grandiflora wall trained (09/07/2011)

This plant may be useful to the landscape architect as a low maintenance, large lowered fragrant tree. This plant may also be trained as a wall shrub/ climber. Frosts may damage the flowers, therefore a warm wall may be its best planting location in colder climates.

The Royal Horticultural Society gave the cultivars Magnolia grandiflora ‘Exmouth’, and ‘Victoria’ their prestigious Award of Garden merit in 1993 and 2002 respectively.

This plant will tolerate almost any soil conditions; it will be happy at neutral, acid or alkaline pH levels, in loam, clay or sand based soils facing any sheltered aspect, except north. The Royal Horticultural Society recommends protection from late frosts.

Ecologically this plant will attract pollinating insects such as butterflies and honey bees however; as this plant is not native to this continent these associations may not be prolific.

Maintenance: It may be trained up a wall as a climbing plant. This requires wires or supports. Shoots growing towards the wall should be removed, outward growing shoots should be reduced to one or two leaves. Specimen trees may be pruned in spring and wall trained specimens may be pruned in summer.