Q: I have this thorny, obnoxious vine growing over some of my shrubs and I want to get rid of it. Can you tell me what it is and how to control it?
A: Your vine belongs to the smilax family and is called Laurel greenbrier, Smilax laurifolia. It is an evergreen vine which produces a large, starchy root. The leaves are alternate, simple with a waxy covering. If left unchecked, it can grow in large masses and cover small trees. It is hardy to zone 8 but it is not uncommon to find it in zone 9 along coastal regions.
Greenbrier produces small, white flowers from July to August. The stems are thorny which makes it more difficult to remove from trees and shrubbery. Be sure to use protective gloves when working with this vine. The flowers are dioecious (similar to holly trees). The individual flowers are either male or female and only one sex is found on a plant. Therefore, both male and female plants must be grown in order to produce the bluish, black berry-like fruit. The plant is not self-fertile. Laurel greenbrier can tolerate any type of light or soil conditions. It prefers moist soil but has been known to grow in sandy, dune areas.
Just a side note – the roots and young shoots can be eaten, so if you are ever lost in the woods this can provide food. Like most troublesome vines, it is best managed by cutting the stem close to the ground and immediately dabbing glyphosate directly onto the cut root area. More than one application will be required depending on how extensive the root system. If possible, dig up the root and remove all of it. Cutting the vine at the soil line and not applying an herbicide will not deter this plant from producing more stems.