Do you have an evil force in your yard that grows more powerful from the warmth of each passing day?
English ivy (Hedera helix), Japanese climbing fern (Lygodium japonicum), kudzu (Pueraria montana), Chinese wisteria (Wisteria sinensis), and oriental bittersweet (Celastrus orbiculatus) are all nonnative, invasive vines of concern in our Georgia landscapes, but there are also a number of plants native to North America that can also cause a huge headache. The Smilax species, also known as greenbriers, are immediately comes to mind.
If controlling weedy vines is on your to-do list this year, be prepared for a fight. Once you begin control efforts, you have to be persistent and act frequently for as long as it takes to gain control over or eradicate the vine. Vines are among the fastest-growing plants, so they can quickly create major problems and rapidly recover from control efforts. Since weedy vines are difficult to control, allowing them to grow unimpeded for extended periods of time makes it all that much harder to get rid of them.
Every situation is different, and gardeners often have to use a variety of methods for best results. Depending on the species, the treatment recommendation may vary, but here are a few basic techniques that I recommend to homeowners. All of these management strategies are effective for pretty much any weedy vine if used persistently over time:
Physical control
The first method is hand pulling and digging out root masses. Get out as much of the below-ground roots, bulbs, tubers or rhizomes as possible. If done regularly, this is a great way to deal with occasional seedlings and lighter infestations.
Physical control also includes cutting down and removing vines from buildings or fences to clean up a situation, followed by digging out the roots and below-ground parts. No doubt about it, physical control measures require a lot of hard work and if you are not able to get out into the yard and wrangle the plants physically, you may need to consider a different approach.
Chemical control
The second method is to carefully spray the foliage with a registered herbicide that cites the particular weed species on its label. This is only a viable option when the spray will not get on the foliage of desirable plants. If need be, nearby plants can be covered to protect them while you spray. Be sure to spray enough to wet the foliage of the vine thoroughly, but avoid excessive application and runoff onto the ground. Done in conjunction with physical control, this method has the potential to be quite effective.
There are multiple methods you can employ. You may spray the vine intact, or cut it back, let it resprout and spray the new growth. Contact herbicides like Roundup are absorbed by the foliage. They enter the plant’s circulatory system, which sends the herbicide into the vine’s roots, killing them as well.
Glyphosate (Roundup, Eraser and other brands) or triclopyr (Brush-B-Gon, Brush Killer and other brands) are commonly recommended for weedy vine control. Triclopyr is generally recommended for woody vines and glyphosate for herbaceous vines. Herbicides that contain a combination of dicamba and 2,4-D also work well, but you must be more careful with these. Once the vine dies, it may be removed
Treating stems
The third method is for larger, established vines growing on trees, buildings or fences, or intertwined in shrubs. In these situations, spraying the vine foliage is not practical because of the potential to injure desirable surrounding landscape plants. It is also unlikely that you would get adequate spray coverage on such a large plant.
Weedy vine control in sensitive areas can best be achieved by the cut vine method. Cut the vine off a few inches above the ground and immediately treat the fresh cut stump with undiluted triclopyr (such as Green Light Cut Vine & Stump Killer). Applying the herbicide to the fresh cut is necessary because it prevents the stump from resprouting. You may have to crawl under a vine-infested shrub to do this. Once you make the cut, the vine in the tree or shrubs will die because it has no root system. The treated stump will die because the herbicide gets absorbed by the freshly cut surface and sent to the roots. This method is very effective, especially if done in fall.
Here is a real life example:
The Smilax species (greenbriers) are difficult to control weedy vines that will entangle through ornamental landscape shrubs. This perennial vine is capable of growing under low light conditions, which allows for rapid growth beneath shrubs to become well established. Smilax has a deep tap root that allows it to re-sprout no matter how many times you chop it down.
As the smilax begins to grow from seed, it sends up a single shoot and produces an underground bulb. As the plant matures, a large cluster of bulbs is created. Only a few shoots will arise from the root mass; the majority of the bulbs lie dormant. If you kill one shoot, that bulb may die, but adjacent bulbs may send up shoots within a few days. Control of smilax should focus on early detection and control before more bulbs are formed.
If you find this noxious vine, a better control method is digging it up rather than chopping it down. Try to get all the bulbs out of the ground. The only other option is frequent sprays of a weedkiller like Roundup or Brush-B-Gon, but herbicides do not easily penetrate into the glossy leaves, so this takes persistence.
Eventually, the root mass will be depleted, but the process may take months, even years! Since Roungup is a contact herbicide, you must take care to not let drift get onto your other plants. One way to get around this is to find where the vine is rooted into the ground, snip it several inches above the soil line, and use a paint brush to coat the above-ground portions with undiluted Roundup. Wear the appropriate personal protective equipment (PPE) and follow the label. Several applications may be necessary before the plant is killed entirely.
Final note:
Try to not get discouraged if early efforts are not as effective as you hoped they would be. Keep at it. If you make a major effort to get rid of the vine and then sit back and let it grow back before you try again, you will never make progress. Persistence is the key. Continuously watch out for unwelcome weedy vines, and be prompt and aggressive in your efforts to control them.
