Chisago County Master Gardener
Ever since I was a girl, I’ve set out each fall to find bittersweet, with its striking orange berries on twisting vines, to use as fall decoration.
It started when my grandfather took us to a spot near Carlos Avery Wildlife Refuge. He taught us to look for the tell-tale chartreuse leaf color indicating that the berries were ready to burst their husks, exposing orange/red fruits inside. I consider spotting bittersweet that is ready to harvest one of my unique talents.
Ten years ago, I decided scouting for bittersweet growing near the road (while driving) was dangerous. So I bought several American Bittersweet plants from a reputable garden center.
I planted them along a split-rail fence and waited years for berries to appear. What I got was sparse, tiny fruits — until this year, when the vines exploded with berries.
But as I waited for them to be ready to cut, I realized with dread that instead of native American Bittersweet, I had planted the highly invasive Oriental Bittersweet from Asia.
Two years ago, the University of Minnesota Extension service published a brief on Oriental Bittersweet and its invasive habits. At the time, I had no idea this villain was on my property, because the plants had been labeled as American Bittersweet.
Since then I’ve learned that one reason Oriental Bittersweet has become such a problem is that growers, unaware they were selling the Asian invader, mislabeled them. And when vines used for ornamentation were carelessly discarded, the berries germinated, creating more plants.
Bittersweet also reproduces by rhizome. I spent a couple hours this year pulling vines that had spread by rhizomes and were overtaking a pine tree.
Now, with heavy heart, I am preparing to cut down my beautiful, woody bittersweet vines. But I respect the research, and seeing how vigorous my plants were, I understand how troublesome Oriental Bittersweet can be.
If you want to know which kind of bittersweet you have, look at the berries. On Oriental Bittersweet, the berries grow all along the stem, and the husk skin is yellow. On American Bittersweet, the berries grow at the ends of the stem. The husk skin is orange.
This is one tough plant, and removal can be difficult. Be sure you eradicate it completely.
And if you use Oriental Bittersweet for fall decoration, discard of it properly. The plant is a prohibited noxious weed in Minnesota.