Poison Ivy

John Wilson

News Column

John Wilson

Extension Educator

August 30, 2013

Poison Ivy

One of my funniest home visits occurred about this time of year several years ago. As we walked around the yard, the homeowner asked me to identify a vine growing up a large tree. I assured her it was poison ivy, pointed out how to identify it, and how to get rid of it.

I must not have been a very good teacher because about 15 minutes later she grabbed a plant in a flower bed with obvious insect damage and asked what was wrong with it. I told her I wouldn’t be concerned about the insect damage, but asked if she recognized the plant. After a few moments of silence, I asked if the leaves looked like something we’d looked at earlier.

A couple more moments of silence were followed with a sheepish, “It isn’t poison ivy, is it?” Our visit was cut short when I confirmed her identification. The only problem was, in those few moments she had also scratched her neck and swatted a couple of mosquitoes. She did take the precaution of having her husband open the door so she didn’t leave any residues from the poison ivy on anything as she headed for the shower.

Anyone who has suffered through the agony of a poison ivy rash learns pretty quickly to avoid the plants whenever possible. Poison ivy is common in uncultivated areas, such as fence rows, roadways, ditches, and woodlands, but it can also find its way into home landscapes. All parts of the plant contain an oil which causes an allergic reaction resulting in the rash.

Learning to identify poison ivy is the first step to controlling it. The old saying is, “Leaves of three, let it be.” This refers to the structure of a poison ivy leaf, which consists of three smaller leaflets. The leaflets are 2-4 inches long, and dull or glossy green in color with point tips. In fall, leaves turn a beautiful orangey-red. The middle leaflet is generally larger than the two side leaflets. The edges of poison ivy leaves are quite variable and can be lobed, toothed or completely smooth.

Plants can grow as an upright woody shrub, a trailing shrub that grows along the ground, or as a woody vine. Vines climb trees quite high and develop a mass of aerial roots along the stem, resulting in the appearance of a “fuzzy rope” growing up the tree. Poison ivy produces yellowish-green flowers, which later develop into waxy, white, berry-like fruits. Birds love these berries and after eating them, spread the seeds.

Poison ivy can be effectively controlled by hand pulling, spot treatment of the leaves with a herbicide or by cutting woody plants down and painting a herbicide on the stump. Hand pulling is most effective on small plants when the soil is moist. Remove each plant’s entire root, because sections of roots left behind can resprout.

Wear rubber, chemical resistant gloves, long sleeves, long pants, shoes and socks to avoid skin contact. When finished, wash clothing and gloves separate from any other family laundry and rinse the washing machine afterwards.

Spot treat individual plants with a selective, brush-killing herbicide containing triclopyr, or a non-selective herbicide like glyphosate if damage to nearby plants is not a concern. The herbicide can be applied anytime during the growing season but it is most effective in late summer to early fall.

Use a sprayer to wet the foliage with herbicide, but avoid soaking the soil or allowing herbicide to drift or splash onto non-target plants. Poison ivy is a difficult plant to control, so repeat applications will usually be necessary. Finally, woody shrubs or vines can be cut down and the stump painted with a herbicide, which will translocate into the roots and kill them.

Once the plants have died, remove them but always use safety precautions when handling dead poison ivy. Even though the plants are dead, the toxins remain. Dispose of the plants completely, but don’t add them to your compost pile or burn them. Inhaling the smoke from poison ivy as it burns can result in an internal rash. If you have contact with poison ivy, wash as soon as possible with soapy water to break down the oily compound which causes the rash. For more information on poison ivy control, contact your local UNL Extension office.