Poison Oak and Ivy
How do I get rid of Poison Oak and Ivy?
Poison oak and poison ivy can be dangerous plants, but they also have positive characteristics. They provide nourishment to a wide variety of animals including many birds, rabbits, deer and bears. They are useful for soil stabilization and erosion control, particularly in areas that have been disturbed. They also make effective natural boundaries.
Native to the United States and flourishing in the Northwest, these plants will be with us for the foreseeable future. Consider leaving poison oak and ivy alone if it is not a threat to people. Poison oak and ivy are only a danger if people come in contact with the plant and its chemical oil, urushiol. This chemical can cause swelling and blisters when it bonds with human skin. Many, but not all people, are susceptible. Some people may not be affected the first or second times they are exposed, but on subsequent exposures have strong allergic reactions.
The first key to avoiding and managing these plants is being able to identify them. (See the Identification page.)
Physical removal, by digging, pulling and cutting the plants out, is most effective. Of course, this requires precautions and protective clothing. The roots also contain urushiol. The plants have long underground root systems that tend to be shallow (about four to six inches deep). Therefore, the digging required is not deep but may disrupt a large area. Once poison oak is removed, it is still dangerous and needs to be disposed of properly. Do not put plants on the compost pile because they remain toxic for years. Debris can be buried on site or raked and bagged for disposal. The disturbed area should be replanted with something else as soon as possible or covered to prevent a resurgence. The best time to remove the plants is late fall, when the leaves are gone and the soil is soft and moist. New sprouts are easier to remove in spring before their roots get established.
Burning Not Recommended
While burning is fast, burning these plants or their debris creates contaminated smoke, that if inhaled, can cause fever, extreme respiratory problems, lung poisoning, or even death. Poison oak often returns strongly after burning if not replaced or otherwise controlled.
Mowing, pruning, sawing and tilling are effective if repeated and maintained, and replacement vegetation is introduced. These methods require vigilance since the root systems remain and must be starved. Late summer is a recommended time to mechanically clear poison oak because the dryness may minimize the plant’s ability to revive. Dust masks should be worn if saw dust will be in the air. Remember all bits and scraps of the plants can be harmful. A thick cover, such as carpet or layers of tar paper, can prevent regrowth after cutting. In fact, if you can bury or cover the poison oak, completely taking away sunlight for several months, this in itself may be enough to kill it.
You should cover as much skin as possible while working with these poison
plants, and remember not to touch your face. (More about exposure.)
Grazing animals, especially goats, have been used successfully to keep poison oak and poison ivy under control. Goats are particularly adept at controlling regrowth and starving the plants by eating their leaves. You will likely need to confine the animals with an electric fence or another enclosure. A few people have even utilized pigs and mules in their control efforts.
You should avoid contact with animals’ fur, which may be contaminated. Beware of pets that may be contaminated with urushiol as well.
According to a recent study, goats fed poison oak do not transfer significant amounts of urushiol to their milk. No problems are known with honey created by bees using poison oak or ivy pollen.
No Chemical Pesticides
For health and environmental reasons, NCAP does not recommend pesticide use. As a further disincentive, repeated herbicide treatments may be required which can hinder the establishment of replacement vegetation. After spraying, removal of plants will still be necessary because of the urushiol.
If removal of poison oak and poison ivy plants is necessary, they should be
identified and then dug or pulled out by the roots, controlled mechanically, or covered to prevent access to sunlight. Grazing animals can also play an important role in the management of poison oak and ivy.
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