Bittersweet- Holiday Wreaths, Keeping Invasives Indoors


This time of the year is one of transition with the falling foliage, waning sunlight, and chilly nights. We flock to the outdoors while the weather is still comfortable. Walking a forested path or driving along a road at a forest’s edge, one might catch a glimpse through the uncovered trees at a vine climbing up brown trunks. People enjoy seeing the bright yellow-red berries popping out from the colorful vine. Their beauty has inspired the people of the Northeast United States and Canada to adorn their homes with seasonal wreaths, but the vine that we enjoy for its aesthetic quality is also a bane to our local environments.

Oriental Bittersweet (Celastrus orbiculatus) was first introduced to America in the 1860’s. A native of China, Korea, and Japan, Oriental Bittersweet is displacing the Native American Bittersweet population, as well as threatening native flora from the ground level to the canopy. As a vine, it starts on the ground, climbing up nearby vegetation, from herbaceous plants, shrubs, and small trees to large, mature trees, ensnaring them all in a thick mass of vines that girdles stems and trunks, blocks sunlight, and potentially uproots its host due to the sheer density of the vines. Oriental Bittersweet has the potential to kill whatever plant it touches. Without the diseases and herbivores of its native home, the vine can proliferate uncontested in a process known as “ecological release.”

Despite its invasiveness, we use Oriental Bittersweet as an autumnal decoration. It was brought to America as an ornamental plant, and is still sold in some nurseries. Thanksgiving would feel different without Oriental Bittersweet wreathes. Our customs welcome this invasive species, but the problem becomes, how can we mitigate its ecological influence while still using it as a seasonal decoration? Thankfully, there are ways to keep Oriental Bittersweet as home décor without it escaping outdoors.

The keys to preventing our holiday wreathes from wreaking havoc on the environment is to harvest the vines while the berries are still green, and to properly dispose of the wreathes after their seasonal beauty wanes. Throwing a wreath outside to transition our decorations from Thanksgiving to the December holidays is detrimental to the health of our local environments. Waiting for the flowers and berries to bloom before harvesting allows the seeds contained in the berries to drop on the ground and grow out of the soil come spring. A single Oriental Bittersweet has the capacity to produce hundreds of berries, each containing two to four seeds. Birds feed on the berries and disperse the seeds as they fly, causing a pronounced disturbance to our forests and wetlands.

With natural processes already assisting the spread of Oriental Bittersweet, we must mitigate its ecological influence through conscious actions. Buying and planting native species in gardens, as opposed to buying invasives from a nursery to plant, helps the native species to survive. Despite some nurseries sale of Oriental Bittersweet as American Bittersweet, we can discern the difference by the position of the fruit and flowers on the stems. “Oriental Bittersweet has fruit and flowers located in the leaf axial along the length of the stem. American Bittersweet, however, only has fruit and flowers in terminal clusters.” (USGS Science for a Changing World). Also, the color of the capsules surrounding the fruit of the Oriental Bittersweet is yellow where as the American Bittersweet has orange capsules.

While Oriental Bittersweet functions both as a festive decoration and a biodiversity destroyer, we must decorate our yards with native species to maintain an ecological balance, lest our wreaths wring our bio diverse worlds dry.


Ossipeelake Alliance
New England Today