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greenbrier weed

Smilax (Greenbrier)

Factsheet | HGIC 2328 | Updated: Jan 11, 2019 | Print

Smilax rotundifolia (called the bullbrier or roundleaf greenbrier) is one of three very common greenbriers in SC. Here it is sprawling over Chinese privet along a creek. Leaves are large, shiny, rounded, and solid green.
Joey Williamson, ©2016 HGIC, Clemson Extension

Smilax species (greenbriers) are difficult to control weedy vines that will entangle through ornamental landscape shrubs. These vines are native to North America. In South Carolina there are ten common Smilax species, along with five less common species. Many common names appear for these troublesome vines, such as catbriers, greenbriers, hogbriers, bullbriers, prickly-ivies, deer thorns, and smilaxes. They are evergreen to partially deciduous plants, produce strong tendrils at joints to aid in support, and are armored with stiff thorns along the vines. Greenbriers are perennial vines and capable of growing under low light conditions, which allows for rapid growth beneath shrubs to become well established.

Greenbrier vines are dioecious, which means there are separate male and female plants. The female plants produce small, ¼- to ½-inch blue-black, black, or red fruit, which are held in small clusters. Birds and small mammals often consume these fruit in winter and spread the seed.

The root systems of greenbriers are typically very extensive, knobby rhizomes that are extremely difficult to pull out of the ground. Each rhizome may sprout additional fast growing vines from several inches to several feet from the original vine.

The rhizomes are capable of quickly regenerating new vines after being cut, damaged by fire, or treated with weed killers.

Larger greenbrier vines are capable of growing upright at least six feet. The production of tendrils allows the vines to stabilize their height by tightly hanging onto shrub branches and low hanging tree limbs. These tendrils are actually modified stems that start out green and pliable, but once wrapped around a branch or twig of a nearby woody plant, they mature and harden. Impenetrable thickets of these thorny vines are often encountered, where they have sprawled over and between nearby shrubs and trees. Using woody plants for support, greenbriers may grow as high as 30 feet.

Greenbrier thorns (actually prickles) may be green and quite small on some species or very large and multi-colored on mature vines of other species, such as on the saw greenbrier (Smilax bona-nox), another one of the common greenbriers in SC. These thorns actually aid in the support of the vines as they snag on nearby branches of shrubs and trees. Some species also have spines along the margins of the leaves to aid in defense from animal browsers.

A third common greenbrier in SC is Smilax glabra (called the cat greenbrier), which can be distinguished from other species by its pale colored, lower leaf surface. The leaves are typically mottled (that is, lightly spotted) but have no spines along the leaf margins.

Not all greenbrier vines are troublesome weeds. The lanceleaf greenbrier or bamboo vine (Smilax smallii) is practically thornless and makes a very attractive climbing vine for training on trellises. The leaves are shiny green, and the vines will grow to approximately 8 feet high. Its fruit are initially a dull brick red, but eventually turn reddish-brown at maturity.

Control

Chemical control of greenbriers is difficult because their extensive root system can regenerate new vines from further back along the knobby rhizomes, and the waxy foliage resists the uptake of sprays. If the greenbriers to be controlled are only a few small individual plants, it is possible to dig up the rhizomes. However, if it is a larger vine, then chemical treatments will be necessary.

Because most chemical sprays may not penetrate the waxy coating on mature foliage, cut the vines and spray after they re-sprout tender new growth. Wait until the regrowth is ½ to 1 foot tall and spray with a 10% solution of glyphosate. To make a 10% solution, add 13 fluid ounces of a 41% concentrate glyphosate product with enough water in a pump-up sprayer to make a gallon of spray. Alternatively, wait until early spring to spray new growth. See Table 1 for examples of products containing glyphosate.

Beneath desirable shrubbery, cut the vines near the soil line and pull out the vines. Immediately paint or spray the freshly cut vine stumps with a 10% glyphosate solution, but do not allow the herbicide to touch landscape plants. Glyphosate has very little soil activity and should not be absorbed by the roots of nearby landscape plants.

Triclopyr is a broadleaf herbicide that is absorbed by the mature foliage of greenbrier vines. Spray the foliage with a solution of triclopyr (9 fluid ounces of a 61.6% product with water to make a gallon of spray, or a 50:50 mix of an 8 or 8.8% product with an equal amount of water). See Table 1 for examples of products containing triclopyr.

Alternatively, spray or brush the triclopyr solution onto the freshly cut stumps of greenbrier vines for control. There is some soil activity with triclopyr, so do not use products containing triclopyr near desirable landscape plants, and do not allow the triclopyr solution to contact the trunks, stems, or foliage of desirable plants. Several triclopyr products are available for use in established tall fescue lawns to control broadleaf weeds, and these can be used to control greenbrier growing there. Follow label directions for use and safety.

Most species of greenbrier in SC have blue-black or black fruit that contain from one to three hard seeds; a few species have red fruit.
Joey Williamson, ©2016 HGIC, Clemson Extension

The long, sectioned greenbrier rhizomes have nodes where roots and new vines arise.
Joey Williamson, ©2017 HGIC, Clemson Extension

Smilax bona-nox has uniquely shaped leaves with basal lobes, the foliage is mottled (lightly spotted with pale green), and the leaf margins have small spines. The fruit are black.
Joey Williamson, ©2016 HGIC, Clemson Extension

Greenbriers, such as this roundleaf greenbrier, grow tall and attach to woody plants for both support and additional height by tightly holding onto branches with tendrils.
Joey Williamson, ©2016 HGIC, Clemson Extension

Smilax bona-nox (called the saw greenbrier) is one of the three very common greenbriers in SC. Its mature vines are armored with large, stiff thorns, and the stems are scurfy (i.e., with a scaly crust on the stem surface).
Joey Williamson, ©2016 HGIC, Clemson Extension

Smilax glabra (called the cat greenbrier) has a pale colored, lower leaf surface (glaucous), bluish-black fruit, and no spines along the leaf margins.
Joey Williamson, ©2016 HGIC, Clemson Extension

Table 1. Post-emergence Spray Herbicides for Control of Greenbrier.

If this document didn’t answer your questions, please contact HGIC at [email protected] or 1-888-656-9988.

Author(s)

Joey Williamson, PhD, HGIC Horticulture Extension Agent, Clemson University

This information is supplied with the understanding that no discrimination is intended and no endorsement of brand names or registered trademarks by the Clemson University Cooperative Extension Service is implied, nor is any discrimination intended by the exclusion of products or manufacturers not named. All recommendations are for South Carolina conditions and may not apply to other areas. Use pesticides only according to the directions on the label. All recommendations for pesticide use are for South Carolina only and were legal at the time of publication, but the status of registration and use patterns are subject to change by action of state and federal regulatory agencies. Follow all directions, precautions and restrictions that are listed.

Smilax species (greenbriers) are difficult to control weedy vines that will entangle through ornamental landscape shrubs. These vines are native to North…

Controlling Greenbrier: How To Get Rid Of Greenbrier Vine

Greenbrier (Smilax spp.) starts out as a lovely little vine with glossy green, heart-shaped leaves. If you don’t know any better, you may even think it’s a wild form of ivy or morning glory. Leave it alone, though, and it will soon take over your yard, twining around trees and filling corners with giant piles of brambles.

Controlling greenbrier is an ongoing job once it gets established, so it’s best to get rid of greenbrier vine as soon as you identify it. Pay attention to the weeds you pull from your flower and vegetable beds so you can identify greenbrier weeds as soon as they pop up.

Greenbrier Plant Control

So what is greenbrier, and how does it appear? Greenbrier vines produce berries that birds love to eat. The seeds pass through the birds and land in your garden, spreading the greenbrier plants around the neighborhood.

If you don’t find and eradicate these seedlings right away, underground stems will produce rhizomes that sprout multiple plants all over the garden beds. Once these plants appear, the vines will quickly grow up any vertical object, including its own stems. Once your garden has been taken over by these vines, it’s very difficult to eradicate them.

Tips on Getting Rid of Greenbrier Weeds

There are two basic methods for greenbrier plant control, and the method you use depends on how the vines are growing.

If you can untangle the vines from your good plants, do it carefully and lay them out on a long sheet of landscape fabric or plastic tarp. Be careful not to break any of the stems, since they can root again very easily. Spray the vine with a 10% solution of glyphosate. Leave it alone for two days, then cut it back to ground level.

Burn the vine to get rid of it; don’t put it in your compost pile. If small plants re-sprout where you killed the larger vine, spray them with the solution when they are 6 inches (15 cm.) tall.

If the vines are completely entangled in your plants, clip them off at ground level. Paint the stubs with a solution that has 41% or greater active ingredient glyphosate. If the small plant re-emerges, spray with the weaker solution just like above.

Note: Chemical control should only be used as a last resort, as organic approaches are safer and much more environmentally friendly.

Controlling greenbrier is an ongoing job once it gets established, so it's best to get rid of greenbrier vine as soon as you identify it. Find out more about the weed and its control in this article.