Cooperative Extension Service
The University of Georgia College of Agricultural and Environmental Sciences
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Mark Czarnota, Ph.D., Ornamental Weed Control Specialist
Department of Horticulture, 1109 Experiment Street
Griffin, GA 30223
Greenbrier (Smilax spp.) is a difficult vine to control in the landscape. There are many common names for Greenbrier, including Catbrier, Cat Sawbrier and Sarsaparillavine. Greenbrier is native to North America. It is in the genus Smilax, which includes about 12 to 15 species. It is in the Liliaceae family, closely related to Daylilies, Lilies and Yucca. With the exception of Smilax pumila (Sarsaparillavine), all species of Smilax are climbing vines (Figure 1). Smilax pumila is a low growing (lower than 2 feet) woody vine (shrub). All species have an extensive underground rhizome tuber system (see Figure 2), and most have spines arising from the above ground stems. The plants are either male or female (a term known as dioecious in the plant world), and females bear fruit ranging in colors from black, blue or red when they ripen. Even though many people hate this plant, it makes many important contributions to the ecosystem. A wide variety of birds eat the fruits, and many forest animals use the foliage and tubers as a food source.
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| Figure 1. Greenbrier (Smilax spp.) growing up a chainlink fence. | Figure 2. A tuber of greenbrier (Smilax spp.) developing rhizomes. |
People often wonder how the vine just seems to appear in their landscape, and why it is so difficult to control. The answer for the miraculous appearance of the vine lies with our avian friends. They consume the fruit and pass them randomly throughout your garden when visiting. Seeds that survive the digestion process and pass from the bird can remain viable for long periods of time. When conditions are right, the seed will germinate. Within a short period of time, plants will begin to develop an extensive underground tuber/ rhizome system and the viney above-ground stem.
Greenbrier is able to survive low light conditions, which enables it to survive deep in the crown of a shrub. It may take 2 or 3 years to emerge from the plant canopy that it has been hiding in. During this time it will have developed an extensive underground rhizome /tuber system.
Once the vine develops an extensive underground rhizome tuber system, it is difficult to control with herbicides. If you have just one plant, physically removing the plant and as much of its tuber/rhizome system as possible is your best option. If physical removal of the plant is not possible, two herbicides are labeled for postemergent application of greenbrier: Campaign® (a mixture of glyphosate and 2,4-D) and Weedmaster® (a mixture of dicamba and 2,4-D). With 2,4-D and dicamba in these herbicides, both formulations are very restrictive -- they cannot be used around desirable woody plants. If you need to remove greenbrier plants growing among desirable woody ornamentals, neither of these products are an option. An alternative would be to apply glyphosate (sold under the trade name Roundup® and others). The following are example situations where glyphosate can be used:
Situation #1: If possible, unravel the greenbrier vine from the desirable plant. Remove as little of the vine as possible, and be careful not to break any of the stems. Lay the vine on some bare ground or on a piece of plastic. Spray or sponge-apply a 5 percent solution of glyphosate (approximately 6 oz of glyphosate/gallon of water, using a product containing 41 percent active glyphosate). Be careful to avoid drift or contact of the spray solution with desirable foliage or bark. Allow the herbicide to stay on the plant for 48 hours, and then cut the stem back to ground level. If the greenbrier attempts to regrow, spray or wipe a 5 percent solution of glyphosate on the sprouts when they are 6 to 8 inches high.
Situation #2: If the greenbrier vine cannot be unraveled from the desirable shrub, cut the vine as close to the ground as possible. Immediately paint concentrated glyphosate on the cut stem. Again make sure that the concentrated glyphosate is 41 percent or greater active ingredient (glyphosate). If the plant re-sprouts, sponge on or spray a 5 percent solution of glyphosate when the sprouts are 6 to 8 inches high.
Trade and brand names are used only for information. The Cooperative Extension Service, University of Georgia College of Agricultural and Environmental Sciences does not guarantee nor warrant published standards on any product mentioned; neither does the use of a trade or brand name imply approval of any product to the exclusion of others which may also be suitable.
Circular 867-2/May, 2004
The University of Georgia and Ft. Valley State University, the U.S. Department of Agriculture and counties of the state cooperating. The Cooperative Extension Service, the University of Georgia College of Agricultural and Environmental Sciences offers educational programs, assistance and materials to all people without regard to race, color, national origin, age, sex or disability.
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Gale A. Buchanan, Dean and Director