Most gardeners agree that gardening would be a lot more fun if we didn’t have to deal with weeds. Weeds are nature’s way of reminding us who is really in charge. Stop mowing the lawn and weeding beds for just one summer, and you’ll see what I mean. Landscapes and gardens exist only because we are willing to put in continuous effort to maintain them.
This time of the year, weedy vines can be a major issue. By late summer, weedy vines have had months to grow vigorously. And the heat makes gardeners tend to take an “I’ll wait until the weather cools down” attitude when it comes to weed control. If you have a weedy vine problem now, however, allowing the vines to grow unimpeded for another month or two will make it all that much harder to deal with them.
Meet the enemy
A variety of vine species can become problem weeds in our landscapes. They are, perhaps, the most difficult weeds to deal with. Vines are among the fastest growing plants. That means they can quickly create major problems and rapidly recover from control efforts. Vines can spread swiftly into new areas, grow to the tops of trees or structures and kill shrubs and lower-growing plants by engulfing them and preventing them from getting light.
When controlling weedy vines, one of the most important things to do is to be prepared for a fight. Once you begin your control efforts, you have got to be persistent and frequent in what you do over whatever period of time it takes to gain control over or eradicate the vine.
Every situation is different, and gardeners often have to use a variety of methods for best results. You may even come up with some creative ideas of your own. There are, however, some basic techniques that are generally effective if used persistently.
The first method is hand pulling and digging out – best done when the soil is moist and soft. It’s very important to get out as much as possible of the below-ground roots, bulbs, tubers or rhizomes. Done regularly, this is a great way to deal with occasional seedlings and lighter infestations. Physical control may also include cutting down and removing vines from buildings or fences to clean up a problem, followed by digging out the roots and below-ground parts.
Spraying with herbicides
The second method is to carefully spray the foliage with a systemic herbicide. This is only possible when the spray will not get on the foliage of desirable plants. If necessary, nearby desirable plants can be covered with plastic sheets or bags to protect them while you do the spraying. Be sure to spray enough to wet the foliage of the vine thoroughly, but avoid excessive application and runoff into the ground. You may spray the vine intact, or cut it back, let it resprout and spray the new growth – depending on the situation.
Systemic herbicides are absorbed by the leaves. They enter the plant’s circulatory system, which sends the herbicide into the vine’s roots, killing them as well. Glyphosate (Roundup, Eraser, Killzall, and other brands) or triclopyr (Brush-B-Gon, Brush Killer and other brands) are herbicides commonly recommended for weedy vine control.
Once it dies, the vine may be removed.
Treating cut stems with herbicides
The third method is for larger, established vines growing on trees, buildings or fences, or intertwined in shrubs. Spraying the vine foliage is not practical in these situations because of the potential to injure desirable surrounding landscape plants. Weedy vine control in sensitive areas can best be achieved by the cut-vine method.
To do this, 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 and 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-infethod is very effective, especially if done in fall. But it can be done any time.
Do 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. Continually watch out for unwelcome weedy vines, and be prompt and aggressive in your efforts to control them.
Dan Gill is a horticulturist with the LSU AgCenter. He can be reached at DGill@agcenter.lsu.edu