Berry Bad: Threat To Trees Lurks On Holiday Tables

Enlarge Urtica/Flickr Creative Commons

Urtica/Flickr Creative Commons

Thanksgiving celebrants, beware. Those fiery red berries in your holiday centerpiece could turn out to be the femme fatale of the plant world.

Asiatic bittersweet is an invasive vine that strangles trees and forest canopies across the Northeast. But its crimson, fruited stems remain a popular decoration on the family table.

That's because in New England, Thanksgiving comes during "stick season" — that time of year when the region's famous fall colors fade and trees stand bare. Asiatic bittersweet's vibrant lure can be hard to resist.

Naturalist Peter Alden says that unlike American bittersweet — a native plant whose berries grow in clusters at the tips of its branches — the exotic species' stems are completely laden with fruit.

"On a mature vine, you have thousands of fruits per plant, and the birds come and eat them and then they poop them all over the place with bird airmail."

Asiatic bittersweet has spread from Maine to Louisiana and the Midwest since it was introduced from Asia in the 1860s. It can climb more than 60 feet, spiraling up the trunks and branches of its host trees like a snake. And like a boa constrictor, it chokes those trees.

Widespread infestations of the plant are nearly impossible to eradicate without herbicides. It's now illegal in many states to collect, move or sell Asiatic bittersweet.

But birds don't heed those laws, and would-be decorators don't always know how to contain the damage.

On a recent episode of her TV show, Martha Stewart herself put together a table display with bittersweet. She mentions that the plant is invasive, and tells viewers to pick it before the pretty berries fall off.

But according to Alden, a lot of people don't know that those berries contain seeds. After the holidays, they may chuck the plants in their compost or the woods.

"Each one of these fruits is an ecological time bomb. Within a few years, these things start growing up and killing the trees you threw them under," he says.

Which makes the legacy of that centerpiece bittersweet, indeed.