(Photo by Patrick Coin.) The leaves of the sweetgum instantly separate it from everything else: nothing else has smooth leaves with five (sometimes seven) lobes, these toothy and when crushed, releasing that distinctive medicinal scent.
By John Nelson
I’ve had a long friendship with this tree, commonly called the sweetgum.
My first recollection of it was while still a small boy, seated outside on a summer morning on the porch and crushing its bright green leaves in my hand, and then enjoying a remarkably pleasant, somewhat medicinal fragrance. Once you’ve taken the scent, so to speak, you’ll never forget it.
The sweetgum is potentially a very large tree, up to 120 or so feet tall. It is a common forest component from southern New England through the lower Ohio River Valley, all the way to Texas and through the upper half of Florida. You don’t see it too much in the higher elevations of the Appalachians, but otherwise it is a standard component of many woodland environments throughout the Southeast. It seems to prefer rich, moist river bottoms and tolerates a fair amount of flooding. It is adaptable to drier settings too, and is a rapid colonizer of old fields and agricultural settings once given a chance.
The bark on large individuals is a handsome grey, finely braided. Twigs commonly bear odd corky outgrowths, sometimes as a series of warty bumps, or perhaps as prominent ridges. (Don’t ask me what they are for. A lot of structures on plants seem to have no apparent utility or function.) But it is the leaves of this tree which instantly separate it from everything else: nothing else has smooth leaves with five (sometimes seven) lobes, these toothy, and when crushed, releasing that distinctive medicinal scent. Indeed, maple leaves are similar in shape, but note that a maple’s leaves are always “opposite” or two-at-a-time on the twig, rather than our Mystery Plant’s, whose leaves are alternate, one at each node. By the way, for autumn color, this species is hard to match. Its leaves are variable from tree to tree, commonly bright gold, but also orange, ruby red or a deep russet. Of course, now in the middle of the winter the leaves will be mostly fallen from the branches; you can still find them on the ground here and there.
The sweetgum is one of those trees which produces both male and female flowers. The male flowers are tiny and in clusters on upright stalks while the female flowers (also tiny) are in globose heads. As the female flowers age, they coalesce into a distinct green ball, which at maturity is hard and prickly, no fun to step on. (And, sure enough, I’ve spent plenty of time raking them up off the driveway. Perhaps you have, too.) In the fall, once the balls are dried and brown, each of the many ovaries making up them up will split open, releasing one or two tiny hard seeds. Birds like them.
You’ll also want to know of this tree’s sap, which once upon a time was used rather extensively for medicinal purposes by Native Americans and settlers. Gashes put into the inner bark will eventually result in plenty of an oozing, clear, aromatic resin…and way back when, this was called “styrax” or “storax.” The solidifying sap has also been used for chewing gum and I remember once trying it. (Once was enough; I’m sticking to Wrigley’s.)
John Nelson is the curator of the Herbarium at the University of South Carolina, in the Department of Biological Sciences. As a public service, the Herbarium offers free plant identifications. For more information, visit www.herbarium. org
Plants of the Southeast is a regular feature in our print edition.