It’s no wonder that florists and crafters enjoy incorporating the vines of oriental bittersweet into their autumn wreaths and decorations—their shiny leaves and vibrant orange berries on twisting woody stems are truly eye-catching. Originally brought to the United States in the 1860s as an ornamental plant, this Asian native has since escaped cultivation. As a perennial vine, it ranks among the most invasive species in North America. Its aggressive climbing nature allows it to spread rapidly, overwhelming and even killing large trees in the process. If left unchecked, oriental bittersweet can create a monoculture, suffocating the surrounding flora.
Bittersweet is harmful to both humans and animals.
Invasive Nature of Oriental Bittersweet
Warning
Oriental bittersweet is rapidly proliferating across the northeastern and midwestern regions of the United States, suffocating and eliminating various forms of plant life through multiple mechanisms. The vines extensively cover surrounding vegetation, depriving them of essential sunlight, air, and water.
Oriental bittersweet generates a large quantity of berries that birds consume, facilitating the plant’s invasive spread through their feces. The seeds can stay in a bird’s digestive system for several weeks, allowing oriental bittersweet to proliferate far from its initial site. Additionally, this plant boasts an impressive germination rate of 95%. Furthermore, oriental bittersweet can also propagate through its underground root system.
How Can You Identify Oriental Bittersweet?
Oriental bittersweet is a perennial, woody climbing plant that can grow as tall as 100 feet. Its shiny, alternate leaves are rounded, have fine serrations, and are either round or oval, featuring pointed tips.
In late spring or early summer, delicate flowers with five petals, colored a pale greenish-yellow, bloom in the axils of the leaves. As autumn approaches, the green berries transform into a vibrant yellowish-orange, while the leaves shift to a yellow hue. Typically, the berries persist on the vine during the winter months, providing a crucial food source for birds, which in turn help disperse the seeds.
Woody vines, capable of growing as thick as 4 inches, wrap around trees, shrubs, and various supports, including artificial structures. The roots of oriental bittersweet penetrate deeply and are notably bright orange in hue.
Ways to Eliminate Oriental Bittersweet
You can manually pull out small vines. It’s important to ensure that you extract the entire root, as bittersweet can regenerate from any remaining root pieces. You can either throw the vines away in the trash or place them on a non-natural surface like a driveway, tarp, or deck, exposing them to direct sunlight for a day or two to effectively eliminate the roots.
If the vine has grown larger and is intertwined with the tree, trim the stem at the base and promptly apply glyphosate concentrate to the cut. It’s important to carry out this procedure during the growing season for it to be effective. Afterward, gently extract the vines from the tree. If the vines are tightly wrapped around the trunk or branches, it may be difficult to remove them without harming the tree. In such situations, cut the vines into sections to remove them. For areas that are out of reach, it is best to leave the vines as they will eventually wither and die.
Once you have applied glyphosate to the cut surface, periodically check the stump to ensure it isn’t producing new shoots. If you notice any new growth, reapply the herbicide as necessary.
Distinguishing Between Oriental and American Bittersweet
Not every bittersweet variety is harmful. One notable exception is American bittersweet (Celastrus scandens), a highly valued native species. This plant is found naturally throughout the central and eastern regions of the United States, with the exception of Florida. If a native bittersweet plant appears in your garden, consider it a fortunate occurrence.
In contrast to oriental bittersweet, American bittersweet features sleek stems and elongated leaves. Additionally, a key difference between the two can be observed in the positioning of the berries: American bittersweet produces berries exclusively at the ends of the vines, whereas oriental bittersweet has berries that develop along the length of the vine.
Regrettably, American bittersweet is becoming more scarce. Compounding this issue is the occurrence of hybridization between the native species and oriental bittersweet.
What is the native region of oriental bittersweet?
Originating from China, Japan, and Korea, it was brought to other regions in the 1860s for use as an ornamental plant and for controlling soil erosion.
In which locations can oriental bittersweet be found?
Oriental bittersweet thrives in both sunny and shaded areas and can be found in a variety of environments such as meadows, grasslands, forests, and their edges, as well as alongside roads and even in sandy dunes and coastal areas.
Does oriental bittersweet harm trees?
Indeed, the robust vines wrap around the trunks of trees so tightly that they suffocate them. As the vines continue to expand, their considerable weight can either snap the tree or pull it out of the ground.
