The sweet gum tree, belonging to the genus Liquidambar, is a large, stately deciduous species native primarily to the lowlands of the southeastern United States. It is a prominent feature of many forests and landscapes, often valued for its impressive size and seasonal color. This species is commonly utilized as a shade tree due to its relatively fast growth rate, reaching heights between 50 and 150 feet at maturity. Understanding its distinct characteristics is helpful for anyone seeking to identify it or manage its presence.
Key Features for Identification
The most recognizable feature of the sweet gum is its distinctively shaped foliage, which is broadly star-like with five to seven sharply pointed lobes. These leaves are arranged alternately on the stem and have toothed margins. This foliage contributes to a spectacular color display in the autumn, often turning brilliant shades of yellow, deep red, and purple.
The tree begins with a narrow, pyramidal shape when young. Mature trees typically develop a broad, rounded, or oval crown that provides substantial shade. The trunk develops grayish-brown bark that starts smooth but becomes noticeably ridged and deeply furrowed with age, sometimes leading to the common name “alligatorwood.”
The Distinctive Fruit
The sweet gum produces a unique and easily identifiable fruit, often colloquially referred to as a “gumball” or “monkey ball.” This fruit is a woody, spherical capsule, typically measuring between one and one and a half inches in diameter, and is covered in numerous sharp, stiff points. Biologically, the structure is a compound fruit formed by the fusion of many individual capsules.
The fruit contains numerous small, lightweight seeds, often winged, allowing for wind dispersal once the fruit opens. The gumball matures during the late summer and early autumn months, turning from green to brown as it dries. While some capsules drop quickly, many persist on the branches, falling gradually throughout the autumn and winter seasons.
Landscaping Management and Nuisance Factors
Despite its aesthetic appeal, the sweet gum tree is frequently associated with several common landscaping challenges, primarily stemming from the large volume of fruit it produces. The persistent, spiky gumballs create a maintenance issue, making mowing difficult and presenting a tripping hazard when they accumulate on walkways and lawns. These woody capsules are notorious for resisting quick decomposition and can remain a nuisance on the ground for many months after falling.
The tree’s root system also requires careful consideration, as it is known for developing aggressive surface roots that can lift and crack sidewalks, driveways, and even damage shallow foundations over time. Successful growth requires moist, well-drained soil that is generally acidic, along with exposure to full sun to partial shade. Due to these issues, many homeowners opt for specific cultivars that mitigate the fruit problem.
Horticultural solutions include sterile varieties, such as Liquidambar styraciflua ‘Rotundiloba,’ which is a fruitless cultivar that still provides the size and fall color of the species. This cultivar is distinguishable by its leaves, which feature rounded lobes instead of the pointed ones found on the fruit-producing variety. These non-fruiting selections allow landscapers to enjoy the tree’s impressive qualities without the associated seasonal cleanup.
Commercial and Historical Uses
Beyond its use as an ornamental landscape tree, the sweet gum is an economically valuable species, harvested extensively for its high-quality hardwood timber. The wood is often marketed commercially under the names “red gum” or “satin walnut,” especially when used for interior applications. Its close grain makes it suitable for manufacturing furniture, cabinetry, veneer, and various types of interior flooring.
Historically, the tree was valued for its resinous sap, known as storax or American storax. This fragrant, semi-liquid substance was traditionally collected from wounded bark and used in perfumery, incense, and pharmaceutical preparations. The resin also saw historical use in folk remedies and was occasionally chewed, which may be the origin of the tree’s common name.