If you make or buy local wreaths this season, watch out for a vine plant with bright red berries.
It may be Asiatic bittersweet, which is classified as severely invasive in Maine and can spread through holiday decorations.
They look striking, but turning them into decorations can invite the quick-spreading, hard-to-remove plant to quickly take over your yard and strangle your trees to death. It’s also illegal to sell the vines in Maine or bring them into the state.
Wreaths or holiday decorations may include other invasive species too, such as multiflora rose, which grows into dense thickets that crowd out other plants.
More than 30 other invasive species have the same restrictions in the state to prevent them from spreading. Different plants have different consequences for the existing environment, but one thing they often do is outcompete native plants. Landscape changes like that reduce habitat and food available to wildlife and pollinators.
Asiatic bittersweet in particular may change soil composition, create habitat for ticks and host plant and tree diseases. It also grows fast and can quickly take over a yard or roadside.
There’s a specific risk to using it in outdoor decorations: birds can eat the berries, spreading the seeds through their digestive system and establishing new plants. As wreaths are thrown out, or if they end up composted, they can spread new plants.
Asiatic bittersweet has no trouble spreading on its own, either. It was brought to the United States as an ornamental garden plant more than a century ago and is considered widespread in Maine.
Once it gets established, it’s especially difficult to remove. One recommended method is to cut it back six times a year. Some people use herbicide on the cut parts to stop it growing back so quickly.
Native plants good for wreathmaking include winterberry, northern bayberry or American mountain ash for colorful berries, evergreens for wreath bases and red dogwood for colored twigs. Although snowberry is another tempting option, it’s not native.
