How to Kill Invasive Vines

Invasive vines introduced to the United States from other parts of the world frequently spread aggressively, taking over large areas and running out native plants. Invasive vines can climb and overtop even very tall trees, plus many invasive species create hard-to-control hybrids with native plants. If that isn't bad enough, invasive vines are hard to eradicate because their dense growth make treating with herbicides difficult. A combination of nonchemical and chemical control methods frequently offer the best control results.

Nonchemical control methods work best in areas where you don't wish to use herbicidal treatments. These methods rely on human power, but you can use tools, such as lawn mowers, pruning shears or loppers, to make the job easier.

Both mulching and smothering work well to eradicate small infestations, and you can boost the vine-killing process by cutting, mowing or treating plants with herbicide beforehand. Keep in mind that these methods also kill valued vegetation and keep desirable plants' seeds from sprouting.

Smothering vines involves laying two or three sheets of thick black or clear plastic over the affected area, extending it out at least 5 feet all the way around the infestation. Anchor the edges and allow the plastic to sit for at least 24 months to kill unwanted plants.

Mulch prevents sunlight from reaching unwanted seedlings so they can't grow, but it doesn't always eradicate mature perennial vines with extensive root systems. Cover the entire infested area with a 6- to 8-inch layer of organic mulch to wipe out annual vines and young perennial seedlings. Grass clippings, wood chips, sawdust, straw or hay make effective organic mulch options. Replenish the mulch, as needed, to keep the layer at its original depth for at least two full growing seasons.

Placing cardboard or newspaper layers at least 9 sheets thick beneath the mulch boosts vine-killing efforts. You must leave this barrier in place for at least two growing seasons for it to work, so replenish the mulch as needed to maintain its original thickness.

Mowing or cutting down invasive vines at ground level can work effectively, but you'll need to do so three or four times a year for as long as five years to completely kill the plants. In fact, the Connecticut River Coastal Conservation District Inc. suggests cutting down large vines, such as Oriental bittersweet (Celastrus orbiculata, U.S. Department of Agriculture plant hardiness zones 4 through 8), close to the soil line as often as every two weeks to deplete the plants' energy reserves and stop them from resprouting.

A few woody invasive vines, including Oriental bittersweet and Japanese honeysuckle (Lonicera japonica, USDA zones 4 through 10), tend to "run" after you first cut or mow them, which initially make the infestations look like they're getting worse. That's because every time you cut or mow the vines, their root systems grow a bit, but the plants must use up their energy reserves to regrow. Be persistent in cutting or mowing the regrowth and you'll eventually kill the entire vine.

Most of the common invasive vines -- including multiflora rose (Rosa multiflora, USDA zones 6 through 8), Oriental bittersweet, English ivy (Hedera helix, USDA zones 5 through 11) and Japanese honeysuckle -- are perennials with long, tough runners and roots. An herbicide containing triclopyr as the active ingredient is often the best tool for treating those plants because it can kill the entire root system without disturbing the soil.

Triclopyr is a systemic herbicide that works because the leaves or stems absorb the chemicals and transfer them down to the roots, which effectively kills the entire plant in about seven days. Triclopyr-based products are effective choices in grassy areas because this selective herbicide kills broad-leaf plants and won't damage monocots, including native grasses.

If possible, time herbicide applications for after native plants go dormant to minimize the danger to valued plants. You can apply triclopyr as long as the temperature is higher than 60 degrees Fahrenheit for at least three days and no rain is expected for the following 24 to 48 hours.

Always read and follow label instructions for personal and environmental safety reasons. This includes wearing a dust mask, long sleeves, waterproof gloves, a hat and protective goggles when mixing and applying the solution.

Foliar sprays typically work best when applied from late summer through early autumn, but no later than 30 days before your area's first expected hard frost.

Triclopyr herbicide

Bucket

Water

Handheld spray bottle or small garden sprayer

Mix a solution containing about 5 percent triclopyr herbicide in a bucket. This typically equals about 20 ounces of product for every 3 gallons of water, but follow the instructions on the product label.

Pour the solution into a handheld spray bottle when treating single vines or very small patches. Pour it into a small garden sprayer if treating larger infestations.

Wet vine foliage completely with the solution to the point of runoff.

Monitor the treated area for several years, making annual herbicide applications if regrowth occurs.

Cut stem treatments typically work best when done in late summer through late autumn. (Ref 1) Avoid getting herbicide on actively growing broad-leaf plants you wish to keep.

Triclopyr herbicide

Water

Pail

Pruning shears or loppers 

Paintbrush, sponge applicator, drip bottle or handheld spray bottle

Herbicide dye or food dye (optional)

Mix together a 25 to 35 percent triclopyr herbicide solution in a pail. This amounts to about 32 ounces of product for every 1 gallon of water, but read and follow the manufacturer's directions.

Use pruning shears or loppers to cut vine stems to within a few inches of the ground.

Apply the herbicide solution immediately to the entire top surfaces of the cut stems. Use a paintbrush, sponge applicator, drip bottle or handheld spray bottle for easy application.

Monitor the area for several years, repeating the process annually until you spot no more regrowth,

Mixing herbicide dye or food dye into the solution stains treated stems so you can easily see which areas you've already treated.