Edward F. Gilman, Dennis G. Watson, Ryan W. Klein, Andrew K. Koeser, Deborah R. Hilbert, and Drew C. McLean
Introduction
Sweetbay magnolia is a graceful southern, evergreen to semi-evergreen, wide columnar tree, ideal for use as a patio tree or specimen. It can grow to a mature height of 50 feet in the north or to 60 feet in the south. Trees glimmer in the wind due to the whitish-green undersides of the leaves. They are very noticeable as you drive by them on interstates along water-logged woodlands. The tree provides excellent vertical definition in a shrub border or as a free-standing specimen and flourishes in moist, acid soil such as the swamps in the eastern U.S. and along stream banks. The creamy-white, lemon-scented flowers appear from June through September, and are followed by small red seeds which are used by a variety of wildlife. It can be trained into a multi-trunked, spreading specimen plant, or left with the central leader intact as a wide column.
Figure 1. Full Form - Magnolia virginiana: sweetbay magnolia Credit: UF/IFAS
General Information
Scientific name:
Pronunciation: mag-NO-lee-uh ver-jin-ee-AY-nuh
Common name(s): sweetbay magnolia, swamp magnolia
Family: Magnoliaceae
USDA hardiness zones: 5A through 10A (Figure 2)
Origin: native to the Gulf and Atlantic Coastal Plains, from East Texas to New York
UF/IFAS Invasive Assessment Status: native
Uses: deck or patio; specimen; street without sidewalk; espalier; tree lawn 4-6 feet wide; tree lawn > 6 ft wide; highway median
Figure 2. Range
Description
Height: 40 to 50 feet
Spread: 15 to 25 feet
Crown uniformity: symmetrical
Crown shape: columnar, vase
Crown density: moderate
Growth rate: moderate
Texture: medium
Foliage
Leaf arrangement: alternate
Leaf type: simple
Leaf margin: entire
Leaf shape: elliptic (oval), oblong
Leaf venation: brachidodrome, pinnate
Leaf type and persistence: deciduous, semi-evergreen, evergreen
Leaf blade length: 2 ½ to 6 inches
Leaf color: green to dark yellow on top, silvery white underneath
Soil tolerances: sand; loam; clay; acidic; wet to well-drained
Drought tolerance: low
Aerosol salt tolerance: low
Other
Roots: not a problem
Winter interest: no
Outstanding tree: yes
Ozone sensitivity: tolerant
Verticillium wilt susceptibility: susceptible
Pest resistance: resistant to pests/diseases
Use and Management
Sweetbay magnolia makes an excellent tree for planting next to buildings, in narrow alleys or corridors, or in other urban areas with limited space for horizontal crown expansion. It has not been planted extensively in downtown urban areas, but its flood and drought tolerance and narrow crown combine to make it a good candidate. It usually maintains a good, straight central leader, although occasionally the trunk branches low to the ground forming a round multi-stemmed, spreading tree. It should be grown and planted more often.
Sweetbay magnolia roots easily from softwood cuttings, grows freely near coastal areas, and is happiest in southern climates. It is thriving in the Auburn Shade Tree Evaluation trials in Alabama without irrigation. However, in the confined soil spaces typical of some urban areas, occasional irrigation is recommended.
The species is deciduous in USDA hardiness zones 7 and 8 (evergreen farther south), but the variety australis and cultivar 'Henry Hicks' are evergreen. 'Havener' has larger flower petals.
Pests and Diseases
Scales sometimes infest foliage and twigs, particularly on dry sites where the tree is under stress.
Tulip-poplar weevil (sassafras weevil) feeds as a leaf miner when young and chews holes in the leaves as an adult.
Leaf spots occasionally occur on the foliage but are of little concern.
References
Koeser, A. K., Hasing, G., Friedman, M. H., and Irving, R. B. 2015. Trees: North & Central Florida. University of Florida Institute of Food and Agricultural Sciences.
Koeser, A.K., Friedman, M.H., Hasing, G., Finley, H., Schelb, J. 2017. Trees: South Florida and the Keys. University of Florida Institute of Food and Agricultural Sciences.
