The safest and most efficient method to control poison ivy is to use an herbicide appropriately labeled for its control minimizing your exposure to the plant. Even after the death of poison ivy, gloves should be used to remove plant parts, because the leaves and vines are still toxic. Brush control herbicides are effective in controlling poison ivy. They can be used safely on poison ivy that is growing along wooden or stone fence rows or in home lawns. These compounds are sold as liquid concentrates, and must be diluted in water before spraying them on the poison ivy foliage. Check the label on the herbicide container to determine the proper mixing ratio. Brush control chemicals usually contain the herbicides 2,4-D, dicamba, and/or triclopyr. These chemicals may be sold alone or in combination with one another under various trade names. Simply spray the foliage making sure to completely cover as much of the poison ivy vines and leaves as possible. After several days, the leaves will turn brown and the plant will begin to die. To get complete control of the poison ivy, it is usually necessary to perform repeat treatments. Be especially careful when applying these materials. Drift of these herbicides caused by wind may injure desired plants in landscape beds or vegetable gardens. These materials should not be used to control poison ivy that is growing in and around trees or landscape beds. Herbicides that contain the active ingredient glyphosate (most commonly sold as Roundup) will effectively control poison ivy when applied in early summer when leaves have fully opened or in late summer/early fall prior to leaf drop. Roundup can be used as a spot treatment to control poison ivy around trees and in landscape planting beds. This can be safely done by avoiding the contact of glyphosate with the foliage of desired plants. Since it is not active in the soil, tree and shrub roots will not be injured. It will kill grass though, so DO NOT use it on poison ivy that is growing in turfgrass.
In situations where poison ivy is growing in and among desired plants, the procedure for control is slightly different. Pull the poison ivy away from those plants, making sure not to pull its roots out of the ground. Lay it on the ground and place several layers of newspaper under it to avoid damaging underlying turfgrass. Dilute the Roundup with enough water so that the chemical only makes up 5 to 10% of the total solution (ex. 3/4 cup to 1 1/2 cups Roundup product containing 40% glyphosate, per gal. of water). Spray this solution on the foliage of the poison ivy, wetting all leaves and vines to the drip point. Allow the treated poison ivy to remain attached to the soil for 5 to 7 days so the Roundup can move down into the root system. Roundup can also be brushed or sponged onto individual poison ivy leaves or vines. One popular method is using the “glove in glove” technique. Place a rubber or latex glove on your hand and cover that with a cloth glove. Dip the gloved hand into a diluted Roundup solution and coat the leaves and vines of the poison ivy plant. The more leaves and vines that are treated, the more effective the application will be in controlling the poison ivy. When poison ivy is growing up trees, cut the vines at head height and allow the upper portion to die. Treat the lower portion with Roundup when the new leaves become fully expanded. In 10 days you can remove the growth. Another option is to cut the vines leaving a 12 inch stump. Immediately brush or sponge a full strength Roundup solution to the freshly cut stump.
Many homeowners encounter a variety of brush species that can become problematic along fence rows, wood lines, and other areas around the home grounds that do not receive frequent mowing. Some of the most common brush species found on the eastern coast include multiflora rose, sumacs, brambles, and hardwood saplings. Free-standing brush and tree saplings can be controlled by several different methods. These methods include foliar, dormant stem, and cut stump applications. Brush control formulations usually contain the herbicides 2,4-D, dicamba, and/or triclopyr (see precautions under poison ivy control). These chemicals may be sold alone or in combination with one another under various trade names. Products containing glyphosate (most commonly sold as Roundup) are also effective for brush control using the foliar and cut stump application techniques. Foliar applications are ideal for controlling small, dense brush. These applications can be performed with the use of a backpack sprayer. Dilute the herbicide with water, making sure to follow the labeled directions to determine the proper mixing ratio. Spray this solution on the foliage of the brush, wetting all leaves and stems to the drip point. This method will provide the best results when treating brush during periods of active growth, from early summer but prior to fall color. Repeat applications may be required to achieve complete control. Dormant stem applications may allow homeowners to control some brush species (most notably multiflora rose and brambles) during winter months. These applications can be performed with a backpack sprayer. Dilute the brush control herbicide with fuel oil or kerosene, making sure to follow the labeled directions to determine the proper mixing ratio. Spray the brush when it is dormant and the bark is dry. Make sure to thoroughly wet the upper and lower stems. Best results are usually obtained during late winter to early spring. Repeat applications may be required to achieve complete control. Cut stump applications are ideal for controlling the resprouting of freshly cut or clipped stumps. These applications can be performed with a backpack sprayer, sponge, or brush. Dilute the herbicide with fuel oil or kerosene, making sure to follow the labeled directions to determine the proper mixing ratio. Spray or coat the top of each individual stump. Make sure that the stumps are cut to a height of 12 inches from the ground. The bark and top of each stump should be thoroughly wet with the herbicide solution. These applications can be made year round, but best results occur from late summer to fall and in early spring. Repeat applications may be required to achieve complete control.
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Brenda Larson is the Horticulture Agent for North Carolina Cooperative Extension in Lee County.