Briars, such as greenbrier (Smilax species) and wild blackberries (brambles), are aggressive, thorny, woody vines that quickly form dense, impenetrable thickets. They are difficult to eliminate because they possess extensive, deep root systems or large, energy-storing tuberous roots, allowing for rapid regrowth even after stems are cut. Complete eradication requires a persistent, multi-pronged approach to destroy the root structure and prevent the plant from photosynthesizing and recharging its energy reserves.
Immediate Physical Removal Strategies
Mechanical extraction demands intense labor and appropriate safety measures against the plant’s sharp thorns and tough, woody stems. Before beginning, wear heavy-duty leather gloves, long sleeves, and thick pants to protect the skin from injury. Cutting the vines at ground level is merely the first step, as this action alone will stimulate vigorous sprouting from the root system.
The only way to ensure the plant cannot regrow is to completely remove the main root system, often called the root crown or tuber. Use heavy-duty loppers or a pruning saw to cut the thickest stems near the soil surface. Trace the remaining vines back to where they enter the ground to locate the primary root structure that must be extracted.
Use a mattock, shovel, or sturdy hoe to loosen the soil around the root crown. Digging must be deep enough to sever the main root below the point where new sprouts can emerge, typically several inches beneath the surface. Thorough excavation is necessary, as leaving even a small piece of the root mass can result in rapid re-establishment.
Targeted Chemical Control Methods
When physical removal is impractical due to the size of the infestation or inaccessible root system, systemic herbicides provide a targeted alternative. The most effective chemicals for woody plants contain active ingredients like triclopyr or glyphosate, which are translocated throughout the plant and into the root structure. Late summer and fall are often the most effective times for application, as the plant is drawing energy downward into the roots for winter storage.
For dense patches, use a foliar spray application, ensuring complete coverage of the leaves without excessive runoff. This method relies on the leaves absorbing the chemical and moving it down to the roots, gradually starving the entire plant. Multiple applications, typically two to three weeks apart, are often required for full control of an established thicket.
A more precise method for thicker, individual stems is the cut-stump treatment, which minimizes impact on surrounding vegetation. Immediately after cutting a stem close to the ground, paint or spray a concentrated herbicide solution onto the fresh cut surface. Saturating the cambium layer, the thin ring just inside the bark, is important as this tissue translocates the herbicide directly to the roots. Immediate application prevents the plant from forming a protective seal over the cut.
Long-Term Non-Chemical Suppression
Alternative, non-chemical methods focus on exhausting the plant’s stored energy reserves over an extended period. Deep solarization is a passive technique where the cleared area is covered with a thick, opaque material, such as black plastic sheeting. This covering prevents light from reaching the soil, cooking surface roots with heat and preventing new shoots from photosynthesizing.
The cover must remain weighted down for a minimum of one full growing season, ideally through a scorching summer, to starve the root system. Another smothering technique involves applying thick layers of cardboard, followed by a deep layer of organic mulch, to block light and suppress regrowth. This physical barrier forces the plant to continually expend energy reserves as new sprouts struggle to penetrate.
In large, heavily infested areas, grazing animals provide an effective biological control method. Goats readily consume the thorny foliage and stems, repeatedly defoliating the briars. Consistent, managed grazing weakens the root system by preventing the plant from recharging its energy stores, leading to eventual decline without synthetic chemicals.
Post-Removal Maintenance and Prevention
Diligent follow-up maintenance is necessary to prevent remaining root fragments or new seedlings from re-establishing the infestation. Proper disposal of removed thorny cuttings is critical, as stems can re-root if left on the ground. Avoid adding them to a compost pile; instead, dry them out and burn them where permissible, or dispose of them in sealed bags through municipal waste services.
The cleared area must be monitored weekly for several months, as remaining root fragments will attempt to sprout new growth. Promptly remove any new shoots by hand or spot-treat them with a systemic herbicide to exhaust the root’s energy reserves. This consistent removal prevents the establishment of new foliage.
To prevent future briar growth, cover the area with a thick layer of mulch or plant competitive ground cover species. A mulch layer of three to four inches suppresses seed germination and shades out minor sprouts. Establishing a dense cover of non-aggressive plants naturally excludes the aggressive briars from recolonizing the area.