Hello Hendra,

Thank you for contacting the UNH Extension Yard & Garden Infoline. My name is Debi Green. I am a master gardener volunteer and I am happy to help answer your question!

It sounds to me like you have Oriental Bittersweet. 

Round leaf bittersweet (Celastrus orbiculatus), formerly called Oriental bittersweet, is an aggressive, invasive species of vining plant that can quickly take over an area and damage even large trees.

Proper identification is the first step for control, especially since we have a native variety of bittersweet that is not aggressive and shouldn’t be confused with the invasive species. Here is a resource on American bittersweet (Celastrus scandens). To compare the differences between the two, see this resource.

Once you’ve properly identified round leaf bittersweet, it’s time to start thinking about control methods. If the plants are small, hand-pulling can be effective. Be sure to get the whole root if you can, keeping in mind the roots can be rather long. For larger, more established vines, chemical control can be the best option. We recommend cutting the vine near the ground and painting the cut surface with a systemic herbicide that will kill the root system such as glyphosate or triclopyr. Don’t try to pull large vines off trees as they can be very heavy and injure you if they were to fall on you. Instead, the vines will eventually lose their hold on trees and fall off.

For more information and more detailed instructions on control methods, please see these resources-

Penn State Extension- Oriental Bittersweet (great description with lots of pictures for ID)

UNH Extension- Invasive in the Spotlight: Oriental Bittersweet

UNH Extension- Invasive Plants: Specific Methods of Control

Since you describe such a large infestation, if you wish to find a professional I have included a link to the NH Landscape Association. https://nhlaonline.org/find-a-professional/

I hope this helps and please ask if you have further questions!