Bittersweet Strangles Trees, Doesn't It?
Updated: Jan 20, 2022
I've learned a lot about native versus exotic plants, trees, grasses and even animals in several decades of working on public parks, open spaces and even my own gardens. When leading volunteers to cut or manage invasives like oriental bittersweet, a very adaptable vine native to Asia, I try to show steps to slow their impact, especially when it comes to impacting trees, both old and young.
When I'm out in public lands, primarily working on trails, drainage, blow-downs (trees or branches across the trail) or flood damage, I can spot invasives that need to be cut back out of the corner of my eye. Often what I think is one or two quickly turns into many. This is an example when I was out a few weeks ago working on a trail.
When you look at this tree, you may think the many branches and vines curled around the tree are part of it - they aren't. Eventually these vines grow longer and fatter and curl up the trunks and out many branches. These vines will grow over many years and eventually put such additional weight on the tree that portions will snap during storms, eventually the whole tree will be taken down.
Obviously, this takes many years and cutting off vines, no matter how big or small, provides relief. After the initial cuts, a volunteer needs to return several times a year for several years to ensure the vines, which will re-sprout, won't re-establish themselves. Eventually, you can declare victory. I focus on cutting them at the base (as flush to the ground as I can get), then as high up as I can reach. I then try and pry off as much of the wrapping vines off the trunk of the tree as I can.
Oriental bittersweet was brought to North America in the mid-1800s as a plant for erosion control, as well as use in decoration, the smaller vines and bright red and orange berries are very attractive for holiday displays and with no known predators, bittersweet thrives in disturbed areas. There are others that we'll cover another time, but in the winter, its really easy to spot and begin the management process, if you know where to look.