The appearance of small, spherical objects beneath or hanging from a tree is a common observation. These “little balls” are biological structures that can represent several different things, including the tree’s reproductive parts, such as fruits or seed capsules, or secondary growths caused by insects. Identifying the source relies heavily on examining the object’s specific texture and the characteristics of the tree itself. This guide will help you differentiate between these common tree structures to accurately identify the species.
Trees Known for Spiky Seed Capsules
The most frequent source of small, spiky balls on the ground is the American Sweetgum tree (Liquidambar styraciflua). These structures are woody, capsular seed heads, commonly nicknamed “gumballs” or “monkey balls.” They are distinctive for their roughly spherical shape and spiky exterior, featuring numerous sharp points.
The mature seed capsule typically measures between 1 and 1.5 inches in diameter, similar in size to a golf ball. Each ball is a complex structure composed of approximately 40 to 60 individual capsules, where each capsule ends in one or two sharp spikes. This arrangement gives the entire structure its characteristic bristly texture, making them a nuisance underfoot on sidewalks and lawns.
These seed capsules begin green while attached to the tree during the summer and then harden and turn brown as they mature. The woody capsules persist on the branches through the fall and winter, detaching and falling to the ground once they dry out. Upon opening, the capsules release numerous small, often winged seeds dispersed by the wind. The presence of these tough, spiky remnants on the ground, especially in late autumn and winter, is a strong indicator of a nearby Sweetgum tree.
Trees Known for Smooth, Hanging Seed Balls
A different kind of spherical structure belongs to the American Sycamore (Platanus occidentalis), which produces smooth, pendant seed balls. These structures are often called “buttonballs” or “buttonwood” because of their neat, round shape. Unlike the Sweetgum’s spiky capsules, the Sycamore’s balls are a cluster of many tiny, tightly packed, fuzzy seeds.
The Sycamore seed ball is about 1 to 1 1/8 inches in diameter, slightly smaller than a golf ball. They hang singularly from long, fibrous stalks, acting like round ornaments throughout the winter months. These balls remain intact on the tree until late winter or early spring, when they break apart.
When the seed balls disintegrate, they release hundreds of individual seeds, each equipped with a small fluff of hair. This material allows the seeds to be carried on the wind, leading to the phenomenon often described as “sycamore snow.” The absence of sharp spikes and their tendency to hang individually on a stalk are the primary characteristics distinguishing them from Sweetgum capsules.
Spherical Growths Caused by Insects
Sometimes, the round objects found on a tree are not reproductive parts but abnormal growths called galls. Galls are plant tissue reactions to the stimulus of an external organism, most commonly an insect like a gall wasp or a mite. The organism, usually by laying eggs or feeding, releases chemicals that manipulate the host plant’s growth hormones, resulting in a defensive, often spherical structure.
These galls are essentially a nursery and a food source for the developing insect larvae inside. They vary significantly in size, color, and texture; some are perfectly smooth and round, while others may be rough or spiny. A common example is the oak apple gall, found on oak trees, which can be up to two inches wide and is often mistaken for a fruit.
The color of galls can range from green or red when fresh to brown or black when old, depending on the plant and the organism that caused it. While they may appear alarming, most galls are cosmetic and do not pose a serious threat to the tree’s overall health. The growth is not a seed pod and is typically found on the leaves or small twigs, rather than dangling from the branches like a fruit.
Identifying Clues Beyond the Ball
For a definitive identification, examine the tree’s other features, particularly its leaves and bark. The Sweetgum tree has one of the most recognizable leaves, featuring a distinct star-shape with five or sometimes seven long, pointed lobes. This star-like structure contrasts sharply with the leaves of the Sycamore.
The American Sycamore has large, broad leaves that are often compared to those of a maple, with three to five shallow lobes. These leaves can grow quite large, sometimes exceeding nine inches across. The difference between the sharply star-shaped Sweetgum leaf and the larger, maple-like Sycamore leaf is a reliable way to tell the two species apart.
The bark of these trees also provides a clear point of differentiation. The Sweetgum develops deeply furrowed, ridged, and scaly bark as it matures. In contrast, the Sycamore is famous for its exfoliating bark, which peels away in patches to reveal smooth, light-colored inner bark that is often creamy white, tan, or green. This peeling bark gives the Sycamore trunk a striking, camouflage-like appearance that is easily spotted, especially in winter.