Poison Ivy, a member of the plant family Anacardiaceae, is one of the most noxious plants growing on the North American continent. Remembered with the lines, "leaves of three, let it be," the entire plant emits an oil, urushiol, which when it come into contact with the skin causes severe itching and rash. Poison Ivy is not a true ivy; it is a woody vine with green leaves that is often confused with other plants such as Virginia Creeper, Kudzu and Blackberry. Poison Ivy forms milky white berries in the autumn that are a favorite food to birds. The vines growing and attached to tree trunks are easy to identify by their hairy appearance. The simplest way to identify poison ivy is by the three leaves, the alternate pattern of the leaf structure and the fact that the plant has no thorns.
Poison Ivy grows best in the woodland areas of North America, but can take root almost anywhere including in rock crevices. The plants can grow as a vine, a bush or as ground cover. The leaves turn a bright red color in the fall and are often the first leaves to turn of the season. Poison Ivy is rare in altitudes higher than 5,000 feet.
Cultivation and Care
Poison Ivy requires no cultivation to become established in a disturbed or wooded area. Extreme caution should be used when working in areas where poison ivy is present. Long pants, long sleeves, gloves, safety glasses and a mask are recommended for safety. Immediately wash any skin areas touched by the plant.
Weed Control Techniques
- Attempting to control poison ivy by hand is not recommended. Herbicides especially formulated for killing the plant are available at any garden center or plant nursery. Most will contain a glyphosate mixture that can be sprayed on the plant. This should be done on a hot, still day so that the spray will not harm other plants in the area. Often, it takes repeated applications to destroy the weed. Poison Ivy vines that have grown on tree trunks can be destroyed using an axe to break the vine from the plant below. The plant itself will have to be destroyed using either a chemical or organic herbicide. Repeated applications of an organic mixture containing acetic acid and oil of cloves can weaken poison ivy plants. Organic measures work best on younger plants and will have negligible effects on mature weeds.* Vinca or other swift growing ground covers can crowd out poison ivy if planted early enough in the season and in sufficient amounts. The use of ground covers does rule out the use of herbicides, whether chemical or organic.