Poison ivy difficult to kill

Q. How can I kill the poison ivy growing in my yard and grass?

Iris from Youngstown

A. Poison ivy is a perennial, woody plant. Thus, it is difficult to kill, depending on the method you choose.

Before starting control, be sure the plant is in fact poison ivy. The plant has three leaflets that appear alternately on the stem. Thus, the saying “Leaves of three, leave it be!” If the plant has five leaflets, it is the often confused with Virginia Creeper vine.

In the lawn and landscape beds, poison ivy was most likely deposited by birds. Thus, the plants will probably be identified when they are still small. At this time, hand pulling is very effective (especially when the soil is moist). Be sure to protect your hands if you are sensitive to the urushiol (the oil toxicant from the plant). Wearing gloves will help, and be sure to wash the gloves and your clothes immediately after doing this. Rinse the washing machine afterwards.

If plants are larger, the challenge begins. Severing the vine just above the ground and treating the wound and subsequent new growth with a nonselective, translocated herbicide (such as one containing glyphosate) will be effective. But multiple applications may be necessary. Other herbicide recommendations are listed by going to the factsheet link below.

There are organic options to consider as well. One of our specialists, Dr. Hannah Mathers, has done a lot of organic weed- control research. She tells us that store- bought vinegar is only 5 percent acetic acid. Using this will result in little or no control on any weeds. To be called a horticultural vinegar for weed control, the product needs to be 15-30 percent acetic acid. Even at this rate, you will need to gain complete coverage and apply several times (maybe over several years) to achieve control on existing poison ivy vines. Thus, you may expire before the poison ivy does. That is why Dr. Mathers recommends, “Scythe [pelargonic acid] if people want to go organic. Scythe will kill larger emerged weeds and will definitely have more activity on perennial vines or shrubs [if the material is very small] than horticultural vinegar ever will.”

If you use any chemical (organic or conventional), be sure to read and follow all label directions. For identification and control options, go to: http://go.osu.edu/ivy

Eric Barrett is OSU Ext. educator for agriculture and natural resources in Mahoning County. Call the office hot line at 330-533-5538 from 9 a.m. to noon Mondays and Thursdays to submit your questions.