Home gardeners often refer to aggressive, difficult-to-manage plants as “bitch vine” due to their persistent nature. This article explains the characteristics of this common garden nuisance and provides strategies for its effective management and removal.
Understanding “Bitch Vine”
The plant most frequently identified as “bitch vine” is Smilax bona-nox, commonly known as saw greenbrier, catbrier, or bullbrier. Other Smilax species, such as Smilax glauca and Smilax rotundifolia, share similar aggressive traits and may also be referred to by this informal name. These woody perennial vines are native to the Southern United States and eastern Mexico, extending northward to states like Maryland, Kentucky, and Missouri.
Saw greenbrier has stout, often four-angled green stems covered with stiff, sharp prickles, especially on lower sections. Its firm-textured leaves vary from heart-shaped to ovate, sometimes showing a mottled pale green pattern on their glossy dark green surface. These alternate leaves have tendrils for climbing, and their margins can also be prickly. Inconspicuous yellowish-green flowers bloom from March to June, producing clusters of small, spherical, black or blue-black berries that persist through winter.
This vine thrives in various habitats, including woodlands, thickets, disturbed areas, roadsides, and fencerows. It adapts to diverse soil types, from dry to moist sands, rocky soils, and rich loams. Smilax bona-nox grows rapidly, reaching lengths of 20 to 30 feet, often climbing into tree canopies or forming dense ground cover.
Challenges Posed by “Bitch Vine”
Smilax bona-nox poses a significant challenge due to its rapid growth. It quickly overwhelms and smothers desirable plants, forming dense thickets that impede access and outcompete native vegetation. This vigorous climbing vine can grow over a foot per week, rapidly ascending trees, shrubs, and fences.
The vine’s formidable thorns, present on stems and sometimes leaf margins, are a major deterrent. These sharp prickles cause painful scratches, making physical interaction difficult and hazardous. The common name “catbrier” references its ability to scratch like a cat.
The plant’s resilience stems from its extensive, deep root system. Smilax bona-nox develops thick, woody rhizomes and tubers that store water and nutrients. These underground structures can be as large as sweet potatoes and extend for yards, allowing the plant to regrow even after top growth is removed or burned. This deep root network makes complete eradication difficult, as hand-pulling often only breaks off the top growth, which the root quickly replaces.
Comprehensive Control and Removal
Controlling and removing Smilax bona-nox requires a multi-faceted approach. When dealing with this thorny vine, wear thick gloves, long sleeves, long pants, and eye protection to prevent scratches and punctures from its sharp prickles.
For young or isolated plants, manual removal can be effective. Digging up the entire plant, including as much of the root system as possible, is the best physical method. Wet the soil to loosen it, then use a sturdy shovel or spade to dig deep and extract the large, knotty rhizomes and tubers. While labor-intensive for established plants, removing these underground storage organs is crucial, as new shoots can sprout from any remaining section.
For larger, established vines, chemical control methods are often necessary. The cut-stem or cut-stump method is particularly effective. Cut the vine at its base, as close to the ground as possible, and immediately apply a concentrated herbicide to the freshly cut surface. This delivers the herbicide directly into the plant’s vascular system, allowing it to translocate to the extensive root system. Herbicides with active ingredients like glyphosate or triclopyr are recommended. A 10% glyphosate solution (approximately 12 ounces per gallon of water) is suggested for painting or spraying directly onto the cut stump. Triclopyr, a broadleaf herbicide, can also be applied to cut stumps.
Foliar spray application is another method, though it can be less effective for established woody vines due to their waxy leaves, which resist herbicide uptake. If using a foliar spray, it is more effective to cut the vines back and then spray the tender new growth when it is about 6 to 12 inches tall. Herbicides like triclopyr or a glyphosate solution can be sprayed onto the leaves, but apply carefully to avoid drift or contact with desirable plants. Multiple applications over time are often necessary to achieve complete control due to the plant’s robust regenerative capabilities.
Preventing Recurrence and Future Management
Controlling Smilax bona-nox is rarely a one-time effort; consistent monitoring and follow-up are essential to prevent recurrence. Regularly inspect treated areas for new sprouts, which indicate residual root activity. Promptly remove any new growth by digging it out or treating it with a spot application of herbicide to deplete root reserves.
Implementing cultural practices that promote a healthy landscape can also deter the vine’s return. Maintaining dense, desirable vegetation can outcompete emerging greenbrier sprouts for light, water, and nutrients. Applying a thick layer of mulch around desirable plants can suppress seed germination and make it easier to spot and remove new growth.
In specific situations, physical barriers can prevent spread. Root barriers installed underground can contain the rhizomatous growth of greenbrier from adjacent infested areas. Landscape fabric can also be used in garden beds to block sunlight and inhibit new sprouts, though its effectiveness is limited against established, deep-rooted systems.
Proper disposal of removed plant material is crucial to prevent re-rooting and further spread. Do not leave severed vines or root fragments on the ground, as they may reroot and establish new plants. Dispose of them in sealed bags or containers, or by burning where permitted.