The sweetbay magnolia (Magnolia virginiana) is a flowering tree or shrub that can be either evergreen or deciduous depending on the USDA Zone where it is grown.
This is an example of a type species, which is a plant that is considered to be the prime example for species in a genus. It was the first species to receive this genus name and other species were later included in Magnolia because of their genetic similarity to the sweetbay.
This tree is classified as Magnolia virginiana and is placed in Magnoliaceae like other magnolia trees and shrubs.
Names that are used with this species include sweetbay magnolia, laurel magnolia, beaver tree, whitebay, sweetbay, swampbay, and swamp magnolia.
Preferred USDA Hardiness Zones
This tree is suitable for inclusion in Zones 5 through 10. Those in Zone 5 should take measures to help protect the tree from winter temperature drops. In the cooler zones, it will be deciduous in habit. It is originally from the eastern United States.
Size and Shape
At maturity, it can be anywhere from 10 to 60 feet tall and 10 to 35 feet wide depending on the climate where it is grown. The tree will be smaller in cooler northern locations.
Sweetbay magnolia can be grown in sites that receive full sun to partial shade.
Foliage, Flowers, and Fruit
The lance-shaped leaves are green on top and silver or white on the underside. Each one is three to six inches long. They are evergreen in warmer regions like the southern United States and deciduous or semi-evergreen to the north.
The white flowers appear as spring turns into summer and are two to three inches across. They have a fragrance that smells like lemons. There are usually fewer blossoms overall on this species compared to others in the Magnolia genus.
This is a tree that attracts butterflies because the leaves serve as a food source for their caterpillars. In this specific case, it will encourage the eastern tiger swallowtail (Papilio glaucus) and the spicebush swallowtail (Papilio troilus) to visit and lay their eggs on the foliage.
Those living in the colder USDA Zones may want to look for the 'Ravenswood', 'Milton', and 'Henry Hicks' cultivars as these have been shown to handle lower temperatures better than the original species.
The 'Mattie Mae Smith' cultivar features leaves that are variegated with stripes of yellow.
You could also use this tree as part of a bird-friendly garden since they like to eat the fruit.
Test your soil before planting the sweetbay magnolia as it needs acidic soil for the best growth. There are methods available to make your soil more acidic if it is close to neutral (7.0) pH. Iron chlorosis may set in if the soil is alkaline.
It should also be moist for optimal results, but this species is also able to grow in wet soils.
Propagation of this species is carried out through seed germination and cuttings.
Maintenance and Pruning
Some trees may start to form multiple trunks. If you want it to have only one trunk, choose the main trunk to train into a central leader.
You may see scales and the tulip tree leaf miner (Odontopus calceatus, also known as the sassafras weevil) on this plant. Scales can be controlled to some degree by using horticultural oil, though this can be difficult since many species have a tough outer layer that acts like armor.
As for the tulip tree leaf miner, try to avoid using pesticides since these may also kill the parasitic wasps that are its natural predators. Insecticides are sometimes used to prevent egg laying and to kill larvae.
This tree is usually free from diseases. You may see some leaf spots develop from time to time.