With silvery leaf undersides that are seen shimmering in the breeze, the sweetbay magnolia is a lovely large shrub or small tree well suited for moist soils. The crowning glories of this plant are the white, lemon-fragrant flowers that appear in spring and summer. Even the red and brown fruits and seeds that ripen in autumn are worth admiring.
Native to the southeastern United States, sweetbay magnolia is surprisingly tolerant of varying degrees of winter cold. In fact, the climate will determine whether the plant remains more of a shrub in habit or attains an upright, tree-like shape. The shorter the summer and colder the winter, the shorter, more shrub-like the sweetbay magnolia grows. Best grown in USDA Hardiness Zones 5 through 9, or Sunset Climate Zones 4 through 9 and 14 through 24, this plant will be deciduous or partially so in colder climates and will be evergreen only in areas where winters are mild, rarely experiencing frosts.
This is perhaps the most important growing requirement for this plant: acidic soil. By conducting a pH test of your garden's soil, you can determine if a sweetbay magnolia will grow readily or if soil amendments are needed to keep the plant healthy. Acidic soils are those with a pH reading lower than 7.0; adding acid-forming mulches and organic matter such as pine bark or needles, oak leaf mold or coffee grounds is beneficial.
Moist to wet soils are found in the sweetbay magnolia's natural habitats, but it adapts and prospers to the average conditions found in a garden setting, too. The soil doesn't need to be deep, but it must retain moisture, even if a sandy soil. Otherwise leaf yellowing and drop occurs continually. Sandy soils need copious amounts of organic matter incorporated, or continual watering. A dry soil, whether loam, clay or sand should be avoided. A soggy, permanently shallowly flooded location is tolerated.
This species grows in full sun to partially shaded conditions. In full sun, receiving at least 8 hours of sunlight daily will create a plant with many branches and leaves and abundant flowering if the acidic soil remains moist to wet. In partial shade, where dappled sunlight occurs for 4 to 6 hours, yields shorter, fewer branched plants and less flowers.
Regardless if attaining only a shrub-like shape or becoming a nice tree, the sweetbay magnolia is best used as a singular specimen. It can be grown in a mixed shrub border in the garden, or as a standalone plant on the edge of a lake, pond or stream. In colder climates where the plant remains more of a shrub, it can be displayed in a large container. This magnolia has shallow roots, so avoid disturbing or injuring the roots around the base of the tree by digging with a shovel or hoe.