Briars are among the most stubborn plants you will ever try to remove from a property, and getting rid of them permanently requires attacking both the visible canes and the extensive root system hiding underground. A single briar plant can send roots several feet deep and spread laterally through underground runners, which means cutting the top growth alone is little more than a temporary haircut. The good news is that a combination of mechanical removal, targeted herbicide use, and persistent follow-up can eliminate even large, well-established stands. The approach that works best depends on the size of the infestation, what is growing nearby, and how much time you are willing to invest.
Why Briars Are So Hard to Kill
The word “briar” is a catchall that covers several thorny, woody plants in the genus Rubus (blackberry and dewberry types), as well as Smilax species (greenbrier or catbrier) and sometimes wild roses. What they share is an aggressive growth habit and a root system that stores enough energy to resprout after almost any single attack. Blackberry-type briars spread by both underground rhizomes and above-ground canes that tip-root when they touch soil. Greenbrier spreads through thick, starchy tubers that can sit dormant for months before pushing new shoots.
This is the central challenge: every method that only removes what you can see leaves the root system intact, and the roots have enough stored carbohydrate to regenerate the plant. Effective briar removal has to either physically extract or smother the roots, chemically kill them, or exhaust them through repeated defoliation over a long enough period that the plant runs out of energy reserves.
Manual and Mechanical Removal
For small patches, physically removing briars is the most straightforward option, though it is also the most labor-intensive. The process involves cutting the canes back to ground level, then digging out the root crowns and as much of the root system as you can reach. A pair of heavy-duty loppers handles most canes, and a mattock or grubbing hoe is far more effective than a standard shovel for prying out root crowns in compacted soil.
The depth of your digging matters more than most people expect. Research on invasive plants with underground rhizomes has shown that fragments buried deeper than about six inches have significantly reduced ability to resprout, and fragments buried below roughly fifteen centimeters often fail to produce any new shoots at all, regardless of size.1Europe PMC. Effect of Rhizome Fragment Length and Burial Depth on the Emergence of a Tropical Invasive Weed Cyperus aromaticus (Navua Sedge) While that study looked at a sedge rather than briars specifically, the principle holds broadly for rhizomatous weeds: the deeper you bury or remove root fragments, the less likely they are to regenerate. For briars, this means you should aim to get every root piece you can from the top foot of soil. Any fragments left closer to the surface will almost certainly try to grow back.
For larger areas where hand-digging is impractical, repeated mowing or brush-cutting is the mechanical alternative. A single mowing does almost nothing to a briar patch except make it angry. The strategy only works if you commit to mowing every two to four weeks throughout the growing season, which forces the plant to draw down its root reserves each time it pushes new growth. Most stands take two to three full growing seasons of persistent mowing before the roots are exhausted enough to stop resprouting. A brush mower or forestry mulcher handles thick, established canes much better than a standard lawn mower, which will bog down or break on woody stems.
Chemical Control
Herbicides are the most efficient way to kill briar roots without having to physically extract them, and two active ingredients dominate briar control: triclopyr and glyphosate. They work differently, and the choice between them depends on what else is growing in the area.
Triclopyr is a selective broadleaf herbicide, meaning it kills woody and broadleaf plants while leaving grasses largely unharmed. This makes it the better option when briars are growing in a lawn, pasture, or grassy field that you want to preserve. Triclopyr is available in two formulations: an amine salt (often sold as Crossbow or Remedy) for mixing with water, and an ester formulation for mixing with oil for basal bark treatments. The amine formulation works well as a foliar spray when briars are actively growing and have full leaf cover, typically from late spring through early fall. The ester formulation mixed with a penetrating oil can be painted or sprayed directly onto the bark of cut stems year-round, which is useful in winter when there are no leaves to spray.
Glyphosate is non-selective, so it kills essentially any green plant it contacts. Use it in situations where you are clearing an entire area and do not need to protect surrounding vegetation, or apply it carefully to individual briar plants using a cut-stump method. To treat cut stumps, you saw the briar cane as close to ground level as possible and immediately apply a concentrated glyphosate solution (usually around 25 to 50 percent) to the freshly cut surface. The freshly cut stem acts like a straw, drawing the herbicide down into the root system. Waiting even an hour after cutting reduces effectiveness because the wound begins to seal.
Timing matters enormously. The single best window for foliar herbicide application on briars is late summer through early fall, when the plants are actively translocating sugars from the leaves down into the roots for winter storage. An herbicide applied to the leaves during this period rides that downward flow straight into the root system. Spring applications are less effective because the plant is pumping energy upward from roots to new growth, which means less herbicide reaches the roots.
A few practical notes on chemical application: surfactants or methylated seed oil added to the spray tank improve how well the herbicide sticks to and penetrates waxy leaf surfaces, which briars have in abundance.2PubMed Central. The mechanism of methylated seed oil on enhancing biological efficacy of topramezone on weeds Most commercial briar herbicide products already include a surfactant, but if you are mixing a generic concentrate, adding one separately makes a noticeable difference. Always spray on a calm day to avoid drift onto desirable plants, and expect to make at least one follow-up application the next growing season. A single treatment rarely achieves a complete kill on a well-established stand.
The Cut-and-Treat Combination
The most reliable method for eliminating a stubborn briar patch combines mechanical and chemical approaches. In late summer, cut all the canes back to about six inches above the ground using loppers, a brush cutter, or a chainsaw for thick, woody stems. Within minutes of cutting, apply a concentrated triclopyr or glyphosate solution to every freshly cut stem. This concentrates the herbicide exactly where it needs to go and eliminates the problem of poor foliar coverage in a dense, tangled thicket where spray cannot reach interior leaves.
An alternative version of this approach works well for scattered individual briars in a lawn or garden. Let the briar grow until it has a good canopy of leaves, then spray only the briar foliage with triclopyr, being careful to avoid surrounding grass and ornamental plants. The briar absorbs the herbicide through its leaves and translocates it to the roots. A foam marker or indicator dye mixed into the spray helps you see what you have already treated and avoid repeat coverage that wastes product.
Using Goats for Briar Control
Goats eat briars with genuine enthusiasm, and they are a realistic option for managing large infestations on rural or agricultural land where chemical use is undesirable. Unlike cattle, which avoid thorny plants, goats actively seek out blackberry and briar canes, stripping leaves and bark and reducing plant height and stem density over time.3Crop Science. Mixed Stocking by Cattle and Goats for Blackberry Control in Rhizoma Peanut–Grass Pastures Research on mixed grazing found that goats alone reduced blackberry biomass by about eleven percent, and goats grazing alongside cattle at higher stocking rates reduced it by roughly thirteen percent, while cattle grazing alone actually allowed blackberry to increase.3Crop Science. Mixed Stocking by Cattle and Goats for Blackberry Control in Rhizoma Peanut–Grass Pastures
Goat browsing works on the same principle as repeated mowing: it forces the plant to continuously use root energy to regrow, eventually exhausting its reserves. The advantage goats have over a mower is that they also strip bark and eat leaves selectively from new growth, which is more damaging to the plant than a clean cut. The disadvantage is that goats eat almost everything, so they need to be fenced away from any plants you want to keep. Portable electric fencing makes it feasible to rotate goats through a briar-infested area in sections. Goat rental services exist in many parts of the United States, and a typical recommendation is to plan for at least two to three seasons of repeated grazing before expecting the briar stand to die out.
Biological Control With Pathogens
In some parts of the world, researchers have developed a different kind of biological weapon against briars: diseases that target the plants themselves. In Australia, where European blackberry is a major invasive weed, a leaf-rust fungus called Phragmidium violaceum has been released as a biocontrol agent. The fungus infects blackberry leaves, weakening the plants over time without posing a threat to native Rubus species or commercially grown blackberry cultivars.4European Journal of Plant Pathology. Use of a trap garden to find additional genetically distinct isolates of the rust fungus Phragmidium violaceum to enhance biological control of European blackberry in Australia This approach is not available to individual landowners as a product you can buy and apply. It is a government-managed biocontrol program. But it illustrates an important point: briars are such a serious weed globally that entire research programs exist to find ways to control them. If you are fighting briars on a few acres, you are not losing to an easy plant.
Smothering and Soil Solarization
For small to medium patches where you do not want to use herbicides, smothering can work, though it requires patience. After cutting the briars to ground level, cover the entire area with heavy-duty landscape fabric, thick cardboard, or multiple layers of overlapping black plastic sheeting. Weight the covering down with rocks, soil, or mulch. The goal is to block all sunlight from reaching any regrowth, which denies the plant the photosynthesis it needs to replenish root energy. Leave the covering in place for at least one full growing season, and ideally two. Any gaps where light sneaks through will allow regrowth, so overlap seams generously and check periodically.
Soil solarization, which involves covering moist soil with clear plastic during the hottest part of summer to heat-kill roots and seeds, can help with shallow-rooted briars but is less effective against deep-rooted species. The heat penetrates only the top several inches of soil, and blackberry roots often extend well below that.
Another smothering approach is deep mulching with wood chips. After clearing the canes, apply a layer at least six inches deep. This is thick enough to suppress most regrowth, especially if you combine it with a layer of cardboard underneath. The combination physically blocks emerging shoots and prevents light from reaching any that push through. Over time, the mulch breaks down and improves the soil, which is a side benefit if you intend to plant something else in the area eventually.
Dealing With Greenbrier Specifically
If your briar problem involves Smilax species (greenbrier or catbrier) rather than Rubus blackberry types, the approach changes somewhat. Greenbrier spreads primarily through large, woody tubers rather than running rhizomes, and these tubers can be remarkably deep and difficult to dig out. A single mature greenbrier tuber can weigh several pounds and sit a foot or more underground.
Chemical control of greenbrier is trickier than blackberry because the waxy, leathery leaves of many Smilax species resist herbicide absorption. Triclopyr applied as a foliar spray works, but often requires a higher concentration and a good surfactant to penetrate the leaf surface. Cut-stump treatment with glyphosate tends to be more reliable for greenbrier because it bypasses the leaf barrier entirely. Many land managers find that a combination of cutting the vine at ground level in summer, treating the cut stems with concentrated glyphosate, and then digging out any accessible tubers gives the best result.
Greenbrier also climbs trees and shrubs more aggressively than blackberry, using tendrils to pull itself into the canopy. If greenbrier has grown up into valuable trees, cut the vine at ground level and treat the stump. Do not try to pull the vine out of the tree, as this can damage branches. The above-ground portion will die and eventually fall on its own.
Preventing Reinfestation
Killing the briars you have is only half the battle. Seeds can remain viable in the soil for years, and birds are prolific spreaders of blackberry seeds. To keep briars from coming back after you clear them, you need to establish competing vegetation that fills the space before new briar seedlings can get started.
In sunny areas, thick turf grass is one of the best briar suppressors. A dense lawn or pasture that is mowed regularly shades out briar seedlings before they can establish. In shaded areas, a heavy ground cover planting or deep mulch serves the same purpose. The key idea is that bare soil is an invitation for briars to return. Any cleared area left bare will likely see new briar seedlings within a year or two.
For pastures, maintaining a healthy, dense grass stand through proper fertilization and grazing management is the most cost-effective long-term briar prevention strategy. Overgrazing thins the grass canopy and gives briar seedlings the light they need to establish. Rotational grazing, where livestock are moved through paddocks in sequence rather than allowed to continuously graze one area, keeps grass healthier and reduces briar reinvasion.
When to Call a Professional
Most briar infestations on residential property are manageable with the methods described above and a willingness to follow up over two or three seasons. But some situations warrant calling a professional land-clearing service or licensed herbicide applicator. If the briar patch covers more than an acre, if the canes are so thick and tall that you cannot safely enter the area with hand tools, or if the briars are growing near water where herbicide application is regulated, professional help is the more practical route. Licensed applicators have access to equipment and formulations that are not available to homeowners, and they can apply restricted-use herbicides that are sometimes more effective on deeply rooted woody plants than over-the-counter products.
Cost varies widely depending on the size of the area, density of the growth, terrain, and region. Expect to pay somewhere between a few hundred dollars for a small lot and several thousand for large-scale brush clearing. Many services include a follow-up visit, which is important because, as should be clear by now, a single treatment of any kind rarely finishes the job for good.