By Scout Nelson
Introduced in 1886 and becoming a pervasive issue by 2010, Round Leaf Bittersweet (Celastrus orbiculatus) has marked its territory across Minnesota’s landscapes. Initially used for its ornamental value, this vine has turned into a formidable adversary for the state’s forest ecosystems.
Despite its beauty, with bright red fruits and yellow capsules that stand out in fall and winter, the vine's charm belies its destructive nature. Thriving unexpectedly in Minnesota's changing climate, Round Leaf Bittersweet was once believed to be restrained by cold weather as it was classified under USDA Plant Hardiness Zone 5—conditions that did not apply to Minnesota until 2012.
The vine's resilience is evident as it lacks natural predators outside its native eastern Asia. This advantage allows it to strangle and overshadow native trees by enveloping trunks and canopies, blocking sunlight essential for tree survival. The additional weight of snow or ice-laden vines can topple trees, leading to significant forest damage as seen in Winona and Red Wing areas.
Recognizing the threat, the Minnesota Department of Agriculture designated Round Leaf Bittersweet as a Prohibited Eradicate Noxious Weed in 2011, banning its sale and mandating the elimination of existing plants.
This swift action by the MDA, coupled with proactive measures from the nursery industry, which removed the vine from sales, marked the beginning of a widespread campaign to control this invasive species.
Efforts intensified with educational initiatives led by the University of Minnesota Extension, supported by various state, county, and municipal partners. These programs equipped thousands of Minnesotans with the skills to identify, report, and manage the vine's spread. Despite these efforts, with 1,938 documented infestations, eradication has shifted from feasible to functional control.
As of 2023, regulation mandates landowners to control the spread of Round Leaf Bittersweet, now listed under Prohibited Control status. However, realistic control measures exceed typical landowner capabilities, often requiring heavy-duty equipment like forestry mowers and chainsaws.
To effectively manage and possibly reverse the spread of Round Leaf Bittersweet, Minnesota may need to allocate more resources towards equipping individuals and communities.
This funding would provide the necessary tools and manpower to sustain efforts against this and other invasive species threatening Minnesota’s natural landscapes.
Photo Credit:minnesota-department-of-agriculture
Categories: Minnesota, General, Weather