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Poisonous Plants, Urushiols and Prevention

© N. Lou Lyons

There is an old saying: "Leaves of three, let them be." If your one of those unfortunate people that has an allergic reaction to urushiol, then "leaves of three, run!" Urushiols are toxic compounds in oil from the leaves of poison ivy, oak, sumac and other plants from the genus Rhus. Itching, blisters, swelling, burning, rashes and redness on the skin are reasons to avoid plants that contain urushiol.

Urushiol (yu-'ru-sHE-"ol) is a word derived from urushi, Japanese for lacquer. This year between 10 and 15 million Americans will develop some type of allergic reaction to this irritating oil. To exlude yourself from the above group of unfortunate people, preventive measures are best.

In order to avoid the plants, it's important to be able to identify them and know where they can be found. Some poisons grow in rocky dry areas, yet sumac grows in wet soil. And don't let the nice little flowers on these weeds deceive you into thinking poison is a wildflower worth touching.

Triple leaflets of three are the hallmark of poison ivy. There are at least four species and subspecies of poison ivy found growing in our state: Toxicodendron radicans (L.) Kuntze; Taxicodendron radicans ssp.negundo (Greene) Gillis;Toxicodendron radicans (L.) Kuntze ssp. radicans; and Toxicodendron rydbergii (Small ex Rydb.) Greene.

Leaves of poison oak Toxicodendron pubescens P. Mill. are similar to poison ivy. Oak poison is found in the states to the south and east of us, and may be in our state in some places.

Sumac poison Toxicodendron vernix (L.) Kuntze consist of a row with six to ten leaflets and one leaflet at the top, or end of the stem. Sumac poison grows around marshy areas.

Contact with poison does not have to be directly from the plants in order to have an affect. Just brushing your clothing against the plant or a pet that has urushiol on it could transfer the oil to your skin and this may cause a reaction. Air from burning leaves and stems of the plants could lead to a bad case of poison, and even clearing brush in the winter may easily give one a terrible case of the itches. Each individual has a different sensitivity to the toxic oil found in poison.

Information provided here is just a brief introduction on how to prevent getting a case of the itches. Further research is recommended. The links below are excellent sources for additional information, especially if your preventative measures fail. May your summer be poison free.

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