Birdwatchers have come to appreciate bittersweet berries as an emergency food source for birds in the winter, including Eastern bluebirds. Both Oriental and false bittersweet are similar to sumac in this respect. All three plants are useful for attracting Eastern bluebirds to your landscape for birdwatching. My sumac article provides information on sumac's uses, history and characteristics.
Arts and crafts folks have also fallen in love with bittersweet (whether Oriental or false). Bittersweet vine can be used, in and of itself, to construct a fall wreath. In addition, smaller portions of vine laden with berries are often incorporated into wreaths composed primarily of other materials.
Stewards of the landscape in the U.S., however, are keeping a close eye on Oriental bittersweet vine. Along with other exotic plants such as purple loosestrife and Japanese knotweed, Oriental bittersweet vine is one of the terribly invasive plants considered by many to be an environmental menace. Oriental bittersweet vines choke out native plants, replacing them with a monoculture. Exacerbating the problem is the fact that, invasive plants or not, bittersweet's vines are so captivating that they entice people to propagate them as a landscaping element. As if Oriental bittersweet vines needed any help in spreading!
Killing Oriental Bittersweet: How to Get Rid of This Invasive Plant
But what if you wish to save your trees and get rid of Oriental bittersweet? Herbicides can be used for the eradication of bittersweet vines; I usually use Roundup (glyphosate) to kill bittersweet. I can also vouch for the effectiveness of Ortho Brush-B-Gon, a triclopyr-based herbicide. The best time to halt the invasion is while the vines are still hugging the ground and have not yet had a chance to climb your trees. Here's how you should use these herbicides in such cases:
- Mix them with water in a sprayer, carefully following label instructions
- Once the plants have leafed out, apply the herbicide on a still, sunny day to the above-ground vegetation
- Re-apply as necessary
But What If Oriental Bittersweet Is Already Too High to Spray?
The instructions above are useful if you have caught the problem in time: namely, before Oriental bittersweet has climbed your trees (to any great height, at least). But what if the problem is already out of hand?
Well, not all is lost. If the invasive vine has carried its invasion into the canopies of the trees, the vine's trunk is probably quite thick. That's the bad news. The good news is that the bittersweet vegetation growing in the canopy is depending upon that trunk: its water supply must come from the roots underground, up through the trunk, and thence to the arboreal vegetation. Sever the connection by cutting through the trunk, and you cut off its water supply.But don't stop there. Immediately after cutting the trunk, daub some herbicide onto the top of the stump that remains. It will be drawn down to the roots, hopefully killing them.
To summarize, there are 3 plants in the eastern and central U.S. commonly called bittersweet:
- false bittersweet (Celastrus scandens):
- if you have false bittersweet on your landscape, you are fortunate: it's a great fall foliage plant
- it is not destructive
- nor is it an invasive plant.
- Oriental bittersweet (Celastrus orbiculatus):
- bittersweet nightshade (Solanum dulcamara), the subject of Page 2:
- unrelated to the two other "bittersweets"
- pretty but poisonous
- the true bittersweet, having been classified as such prior to the other two
If the charms of Oriental bittersweet lure you into growing it on your property, at least take precautions against the spread of this highly invasive plant. Keep it confined to one area of your property by ruthlessly suppressing infestations elsewhere. Where you are allowing it to grow, visit often with your pruner; with proper attention, it is possible to tame Oriental bittersweet, restricting it to bush status. And if you are going to train it to grow vertically, construct a large trellis, or tie the vines to a fence. Do not allow Oriental bittersweet to grow on any tree whose health you value.