The joys of summer in the woods: a lesson in poisonous plants

By Beth Whipple, Portage County Master Gardener Volunteer

The joys of summer, walks in the woods, trips to the park, camping, but wait— what are those plants? And now I have an itchy rash! Poison ivy, poison sumac and poison oak: these are three of the common poisonous plants which can cause rashes when we encounter them in the woods and at home.

What can we do? What do these plants look like?

These plants contain urushiol, a toxic oil that causes allergic reactions in most people, leading to rashes and itching.

Poison ivy: A simple way to identify poison ivy is the old saying: “Leaflets of three, let it be.” Its compound leaves have three leaflets, with the middle one attached to a longer stem. Look for reddish stems, an alternating leaflet pattern, thick hairy vines, and small white or yellowish berries.

Poison ivy can grow as a shrub or vine (up to 150 feet), in sun or shade. All parts contain urushiol year-round, even without leaves. The plant always has three leaflets, which may be toothed or smooth, and the center leaflet’s stem is longer. Its clustered, round white fruits attract birds and deer. Virginia creeper is similar but has five leaflets and blue-black berries.

Poison oak: Poison oak is a shrub that typically grows up to 3 feet in height. It is commonly found in dry, sunny areas and is not often present in dense shade. The plant has lobed leaves resembling those of an oak tree, which are generally about 6 inches long. The central leaflet tends to have similar lobes on both sides, while the two side leaflets often display irregular lobing.

Poison sumac: This plant is commonly found in southern regions and grows as a small tree in wetland environments. Its leaves are composed of 7-13 leaflets arranged in pairs with a single terminal leaflet. The leaflets are elongated, oval-shaped, and have smooth edges. Poison sumac also features reddish stems. OSU Poison Ivy, Oak and Sumac

Helpful hints to remember: OSU Poison Ivy, Poison Oak, and Poison Sumac

• Avoid touching poisonous plants while working.
• Urushiol can stay on unwashed clothes for years.
• Wear protective clothing around poisonous plants.
• Never burn these plants; inhaling their smoke is dangerous.
• Apply rubbing alcohol immediately after contact.

If water is available, immediately wash the affected skin with cold water to reduce the risk of urushiol absorption; this is most effective if performed within five minutes of exposure. If within the first 30 minutes, thoroughly clean the area using soap and water.

For rashes, use warm compresses or cool baths.

Try over-the-counter itch relief as directed.

For severe reactions, seek medical help.

What if these plants are in my yard

Cultural Control Methods

Poison ivy can be controlled by repeatedly mowing or cutting it at ground level over several years, making herbicides unnecessary in lawns. Prevent spread by managing poison ivy in nearby wooded areas. For small garden beds, dig out plants and roots, and always wear waterproof gloves to avoid skin contact.

Herbicide Control Methods

A variety of herbicides can be used to manage poison ivy. Always carefully read and follow the herbicide label, paying close attention to recommended application rates, droplet size, wind speed restrictions, and temperature limitations.  Remember the label is the law.

Due to poison ivy’s extensive root system, more than one herbicide treatment is often needed to achieve effective control. Treatments are recommended during the full-leaf stage of growth. Controlling Poison Ivy in the Landscape

Ohio State University Extension Portage County Master Gardener Volunteer program. Questions/comments/suggestions/want to find out more/become a PCMGV: 330-296-6432 • OSU PCMGV web • portco.mgv.oh@gmail.com • FB PCMGV • PCMGV Speaker’s Bureau