The Enemy - White Bryony (Bryonya alba) is also known as Western kudzu, this perennial climbing vine that can grow up and cover the top of your trees in a single season. This invader was brought into the United States for medicinal purposes and has spread throughout eastern Idaho. It has large leaves and produces green berries that turn dark purple in late summer that can become toxic to kids if eaten, but it is actually an expectorant, which will cause one to throw up very quickly. If your vine has a woody stem and has whisker-like flowers it is Western clematis not White bryony.
The Strategy - The plant grows each year from a large tuberous root (resembling a sugar beet) and is not selective what it climbs. Its seeds are a food source for birds, which deposits the seeds under the trees and fences. The plants climb up trees and shrubs and smother them from valuable sunlight and the weight from the plant will break off branches.
The Defense - This is a very difficult weed to control. We have been told that one can inject straight Roundup into the tuber for control. Furthermore, drilling 3/8 holes into the tuber and then pouring a 50% solution of Roundup into the holes will work okay. There are a number of other herbicides that work, but they will also kill the tree or shrub that the plant is climbing. So far the best tool that has been found is to simply dig it up; bearing in mind that each fibrous root-hair left behind will develop into a new tuber. Place the tuber into the garbage, for throwing it back on the ground will allow the plant to re-root. As always do not hesitate to call your county weed control office for additional help.
PLEASE NOTE - The proper use and application of herbicides can be an effective way to control and eradicate noxious and invasive plants. Before using herbicides, always carefully follow the label and safety instructions on the label. While we recommend the use of herbicides as one of the effective tools for integrated pest management, the Idaho Weed Awareness Campaign assumes no liability for herbicide applications.
For more information, click on the link below to download the Idaho's Noxious Weeds Control Guidelines publication produced by the University of Idaho Extension.
U of I Idaho's Noxious Weeds Control Guidelines (183 KB PDF download)