Poison ivy has a characteristic compound leaf consisting of three leaflets. Hence the saying, “Leaves of three, let it be.” The leaves are 2 to 4 inches long and dull or glossy green with pointed tips. The middle leaflet is generally larger than the two laterals. Mature poison ivy vines growing up trees flower and produce a white fruit that’s readily eaten by birds. The birds spread the seeds through their droppings, causing the wide occurrence of this plant.
Three methods can be effective in eradicating poison ivy in landscapes.
The first is hand pulling or digging it out when the soil is moist; getting out as much of the roots as possible. Use long-gauntlet, rubber gloves available at local hardware stores or use dishwashing gloves when handling the vines. Place the plants into a plastic bag, seal it (in consideration for trash collectors) and throw it away. Be sure to wash your gloves with soap and water after handling poison ivy.
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 needed, nearby desirable plants can be covered with plastic sheets or bags to protect them while you do the spraying. Be sure to wet the foliage of the poison ivy vine thoroughly.
Systemic herbicides are absorbed by the foliage and enter the plant’s circulatory system, sending the material into the vine’s roots and killing them as well. Glyphosate (Roundup, Eraser, Hi-Yield Killzall and other brands) or triclopyr (Brush-B-Gon, Brush Killer and other brands) are commonly recommended for poison ivy control. Herbicides that contain combination of dicamba (Banvel) and 2,4-D also work well. Once the vine dies it may be removed. The dead leaves still contain the rash-causing oils and should be handled cautiously with gloves.
The third method of removal is for larger, established vines growing up in trees or intertwined in shrubs. Spraying the vine foliage is not practical in these situations because of the potential to injure desirable trees and surrounding landscape plants. Poison ivy control in sensitive areas can best be achieved by the cut-vine method.
Cut off the vine a few inches from the ground with loppers and immediately treat the surface of the freshly cut stump with undiluted triclopyr (Brush-B-Gon, Brush Killer, Greenlight Cut Vine and Stump Killer and other brands). The vine in the tree or shrub will die because it has no root system. The treated stump will die because the herbicide gets absorbed by the freshly cut surface and translocates to the roots. Applying the herbicide to the fresh cut is necessary because it prevents the stump from resprouting. This method is very effective and may be used any time of the year.