Plant Type, Taxonomy of American Sweetgum Trees
Plant taxonomy classifies American sweetgum trees as Liquidambar styraciflua. The type recommended in this article is Liquidambar styraciflua 'Rotundiloba,' a sterile, non-fruiting culitivar (that is, it does not produce the famous balls known as "gumballs" that serve as seed pods).
Characteristics of the Plant
The leaves, which are five-lobed and shaped like stars, provide excellent fall foliage color. In some cases, at the peak of the fall foliage season, some leaves may be red, others purple, others yellow, others orange -- all on the same sweetgum tree. On some trees, the branches are "winged," as on winged euonymus (burning bush), displaying corky flanges. The bark on the trunk is deeply furrowed.
Most people consider their seed pods (also called "fruits," "balls," "gumballs," "capsules") to be messy, although they are hardly the nuisance that the fruits from a female Ginkgo biloba are. Not only are they messy for you, but they are also potentially messy for your neighbors. If you live uphill from a neighbor, the gumballs may roll downhill onto the neighbor's property when they drop.
That is why the fruitless 'Rotundiloba' is the recommended cultivar to grow. Rotundiloba grows 60-70 feet tall with a spread not even half that, which helps give it a narrowly pyramidal form.
USDA Plant Hardiness Zones, Preferred Growing Conditions and Care
American sweetgum trees are best grown in USDA plant hardiness zones 5-9. They are drought-tolerant trees once established. Grow them in full sun and in loamy soil that is on the acidic side. Fertilize them occasionally with compost.
When You Can't Find the "No-Gumballs" Variety
Although most find the spiky pods (which look like they belong on a medieval weapon) messy, they do have their uses.
Craft enthusiasts use them decoratively in, for example:
- Christmas kissing balls
- Christmas wreaths
- Dried floral arrangements
Some gardeners report success using them as a "pest-control mulch" (critters do not like stepping on their spines). Wildlife (birds and rodents) eat the seeds.
But if you are not involved with crafts -- and if you dislike unnecessary landscape maintenance -- you probably will not be a fan of these gumballs. If you can't find the pod-less 'Rotundiloba,' but you still wish to grow American sweetgum trees, plant them in an area where you will not have to bother cleaning up the pods. For those with sufficient room on their properties, one option may be to incorporate the "messy" sweetgum trees into woodland gardens.
Outstanding Features of American Sweetgum Trees
American sweetgum trees are moderate-to-fast-growing trees. But such practical issues aside, their best feature has to be their fall foliage color, which is not only rich, but also varied. You will appreciate the fact that you can get more than one autumn color on the same tree, which is also true of some maple trees.
Another good feature of this plant is that its fall foliage develops rather late in the autumn (November in zone 5), meaning that it gives your landscaping color after the leaves of the sugar maples and red maples (for example) have dropped off their branches.
Name Origins, Uses in Landscaping
These trees do yield a type of gum called "liquid amber," thus accounting for both the genus name and the common name. According to the Illinois State Museum, "The sweetgum sap is also referred to as American styrax (hence the specific epithet, styraciflua) and some use it as a chewing gum."
The Cornell University Extension observes that this gum has also been used medicinally to, among other things, "ease sore throats, coughs and colds." Meanwhile, "Rotundiloba" refers to the leaves' rounded lobes on the fruitless cultivar (think of the adjective, "rotund").
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