Poison Ivy

Poison Ivy (Toxicodendron radicans) is infamous for causing severe rashes, caused by most humans' allergy to urushiol. Urushiol is the oily sap created by all parts of the plant, including the leaves, stems, and even roots. The oil provides a protective coating for the plant, but is harmful to humans, especially those with a more severe reaction to it. Despite this, Poison Ivy is an important native plant that provides food and cover for wildlife.

Most people know the rhyme: “Leaves of three, let it be.” Although some three-leafed plants, like wild strawberries, are perfectly harmless, it is always safest not to go near a plant if you are not certain of its identity. In general, Poison Ivy grows as a short shrub, but it can also grow very low to the ground as small seedlings, as a vine on trees, or almost as large as a tree itself. The leaves come in many different shapes and sizes as well, so it can be difficult to identify. They range from light green to dark in color, and can turn red, orange, or yellow in the fall. All Poison Ivy leaves are grouped in clusters of three, which grow on their own stem coming off of the main vine, with the center leaflet having a longer stalk than the others. The leaves have smooth and shiny surfaces due to the urushiol on them. They can have ridges or be smooth around the edges, but are almost never saw-toothed. Poison Ivy never has thorns.

Poison Ivy reproduces through the use of flowers and berries, which are eaten by wildlife, including many species of birds and deer. Most animals are unaffected by Poison Ivy's urushiol, which is important to know if you have a dog. Your dog can get urushiol on its coat and affect you, even if you do not touch Poison Ivy. It is also important to note that dead Poison Ivy can still have urushiol in it for weeks or months.

Urushoil can be washed off with soap and water, so if you have touched Poison Ivy you should do so before the oil is absorbed by the skin, which can be as soon as 10 minutes. Since it is an oil, washing with only water will cause urushiol to spread, worsening the reaction. If you get urushiol in your eyes, mouth, or other sensitive area, get medical attention immediately. Despite its unfriendly nature to human skin, urushiol can be useful, as it forms a hard lacquer, used in China, Korea, and Japan for traditional lacquerware.

Other plants related to Poison Ivy include Poison Oak (Toxicodendron pubescens) and Poison Sumac (Toxicodendron vernix). Both are in the same family and produce urushiol. Poison Oak is not native to New England, but Poison Sumac is. Poison Sumac can grow to be a shrub or up to a 30-foot tree, having long pointed, compound leaves, usually green but sometimes tinted red. Poison Sumac has berries of a creamy white color, giving it the less popular nickname white sumac. People are less likely to directly encounter Poison Sumac since it is almost always found in wetlands.


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Created in 2015 for Shinji Coram's Eagle Project