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Toxicodendron radicans


Poison ivy can often be a nuisance to park visitors and employees. However, as a plant it has considerable wildlife value. The white waxy berries are a popular food for songbirds during fall migration and in the winter when other foods are scare. Robins and grosbeaks especially like the berries. Many birds feed on insects hiding in the tangled vines. Small mammals and deer browse on the poison ivy foliage, twigs, and berries. For this reason, management of this plant should be carried out only when the plant directly interferes with the mission of the park and/or represents a safety or health threat to the public.


Identification: This woody plant is commonly confused with other plants. Poison ivy grows as a shrub or as a climbing or creeping vine. The plant has three leaflets on long, oppositely placed stems (petioles). The leaves, some up to 10 inches in length, can be glossy or dull green, hairy, smooth, evenly margined or slightly toothed. The fruit which appears in mid summer, is a dry, grayish-white drupe, or stone fruit.


Life cycle: Poison ivy is perennial, reproducing every year from seed and from an existing rootstock that can creep out from the original plant 10 or 15 feet.


Environmental conditions that favor development: Poison ivy grows best in good light, rich soil, but it will grow in poor soils, heavy shade, and on disturbed sites. Poison ivy is very often found along fencerows, field borders, and under powerlines, where birds passively carry the seeds in their droppings.


Medical importance: The toxic in poison ivy is an oil which causes an irritating skin reaction on many people. The reaction, an itchy rash with clear blisters, is variable in severity among people, and can vary from year to year on the same individual. Poison ivy plants should never be burned, because when heated the oils in the plants vaporize and can be breathed into the lungs accidentally. Human lung tissue is very susceptible to the oil of poison ivy.


Potential damage: Poison ivy is not known so much for the physical damage that it does, but more so for the visual damage. Poison ivy, left unmanaged, will crawl up and cover fences, structures, trees, and power poles. This type of unchecked growth is often judged to be unsitely when it occurs in the wrong place.


Threshold: Poison ivy is a valuable native plant, with considerable wildlife value. In sites where it does not pose a visual or safety problem to the visitor or park employee, the threshold can be very high. Only when poison ivy moves into the developed zones of park units, where it is likely to present a problem for the park visitors and park employees alike, should management be considered. In situations where poison ivy has moved into developed areas, the threshold is quite low! Cutting and removal of all plants, before they can spread and develop significant root systems should attempted.


Monitoring: As with any pest issue, it is impossible to evaluate the success or failure of management actions with monitoring information. A systematic, repeatable monitoring process should developed for the park site. Information should be collected on a regular basis, and should be continue even after the pest seems to be gone. Maps of the park site should be drawn, showing treatment sites, with information about the health of the plant before and after treatment. This information is priceless when evaluating option for future poison treatment efforts.


Care should always be taken when removing Poison Ivy plant material. The employees working with the plants should always where protective gear and should take great care not to wash their clothes with other non-contaminated clothes. Tools should always be washed carefully after each use to prevent unnecessary skin outbreaks. Done correctly, safe management of poison Ivy can be accomplished. For protection, you can use various products such as MultiShield applied prior to anticipated exposure to Poison ivy oils or Tecnu Skin Cleanser to cleanse exposed skin.


Cultural Management Comments When By Whom
Public and Employee education A Poison ivy plant can grow as a vine or as a scrub in the Northeastern US. The leaves of the plant may be small, large, shiny, dull, toothed, or smooth edged. Many visitors who come to visit parks think they know what poison ivy looks like, but are often surprised to find that they are holding a poison ivy plant that doesn’t look at all like the "poison ivy" they have at home. Education on plant identification and the value of poison ivy in a natural setting needs to be offered. Employee training can occur at any park meeting. Visitors can be offered education information as they enter a Visitor Contact Area.  


Mechanical Management Comments When By Whom
Cut and remove poison ivy plants that are in developed zones of park units. Care should be taken in the removal of poison ivy plants. The person cutting the plant should wear protective gear that covers their face, hands, limbs and body. All tools should be cleaned carefully to remove any oils that might have come from the ivy plants. Cut plants should be moved to out of the way sites in the woods or buried. NEVER BURN POISON IVY PLANTS!!! Best accomplished in the winter when the plants are dormant.  
Dig up and remove troublesome ivy plants. When poison ivy plants are still small, removal of the plant can often be accomplish by digging it up. Disposal of the plants should in the woods. Always wash tools carefully to remove any oils that might remain. Best accomplished in the winter when the plants are dormant.  
Mulch and bury Some landscape managers recommend mulching ivy plants into very small pieces and then burying the remains. Best accomplished in the winter when the plants are dormant.  


Chemical Management Comments When By Whom
Glyphosate Poison ivy can be very persistent, so it is commonplace to spray a problem plant several times with a well timed herbicide before control is possible. Products with Glyphosate as an Active Ingredient have work well in the management of Poison ivy. Best carried out in the late Summer or early Autumn when the plant is pulling nutrients down into the roots in preparation for winter dormancy.  


Last Update:
Feb. 3, 2011
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