THE ISSUE:  White bryony   

White bryony (Bryonia alba) is a perennial climbing vine that is native to Eurasia. It was originally introduced into the U.S. in the 1970’s. It invades residential and other forested areas. It causes significant damage as it climbs trees, shrubs, and structures. All parts of this plant are poisonous to humans and livestock, especially the roots and berries. 

 White bryony vines can grow up to 12 feet long, forming dense mats of vegetation on trees and shrubs. White bryony can block out sunlight, which can kill the host species, or it can cause branches to break off when loaded with snow. It grows extremely fast, up to 6 inches per day.  It has dark green leaves that are palmately lobed. Each leaf is associated with a tendril, allowing it to grasp on to a tree or shrub, giving it stability as it climbs. It has a stout root system that can be up to 18 inches in length. Flowers are white to yellow or yellow to green in color and are approximately ½ inch in diameter. Each flower has 5 petals and is found in clusters at the leaf axil. Green berries develop, as they mature, they turn black in color. 

Integrated Pest Management (IPM) Options: 

• Prevention— Learn to identify this plant. Never transport unknown plant material.  

• Mechanical— Digging out the roots of White bryony can be an effective control method if done correctly. Dig out roots in the fall after the leaves have died back and ensure that the roots are cut 3-5 inches below the soil surface. After removing White bryony monitor the area closely, digging out regrowth as needed. Make sure that you wear protective clothing as this weed is poisonous.

• Chemical— Glyphosate when applied using the ‘cut stem’ method is an effective control method. This method can be used any time of the year. Cut stems 3-4 inches below the soil surface and then apply concentrated glyphosate to the cut stems (just enough to wet the surface). This allows the glyphosate to penetrate the root system, providing good control.  Glyphosate is a non-selective herbicide, and it will kill other vegetation it contacts. Always read and follow herbicide label directions!

Justin Hatch, University of Idaho Extension Agriculture Educator in Caribou County. 208-547-3205 [email protected]