Last modified on 20 April 2011, at 02:33

Organic Horticulture in the Mid-Atlantic/Poison ivy

Toxicodendron radicans (Poison Ivy)

Toxicodendron radicans (poison ivy) is a deciduous woody vine or shrub common throughout the Mid-Atlantic, and is one of the most problematic weeds because the oils it contains causes severe rashes in most people.

The plant can be difficult to identify because the leaflets have a great variation in shape, but they are always trifoliate, alternate on the stem, and usually have a reddish petiole. The bark is a warm gray color to cinnammon reddish brown. Mature vines exhibit hair like rootlets resemble rusty steel wool when climbing. Like English ivy and many other climbing vines, the mature form has branches that grow perpendicular to the main vine produce small yellowish white flowers and greenish looking fruits. Flowers are yellowish green in early summer, while the white/grey drupes (seeds) mature in autumn, often persist through winter.

All parts of the plant contain the oil urushiol, which is the chemical responsible for causing an allergic reaction (Urushiol-induced contact dermatitis). The toxin is present all year, and persists in dormant branches and dead fallen leaves.

The prolific plant seeds are spread by wind, small rodents, and birds. The drupes serve as an important persistent food source. Once spring arrives seedlings will be found growing anywhere birds, mammals congregate, particularly where they perch or hide, such as on fences, shrubs, and small trees.

RemovalEdit

Removal of poison ivy requires special care, especially by susceptible individuals. Slightest skin contact can be neutralized by "washing" the skin immediately with soil to bind the urushiol (urushi oil), and there are a number of soaps available to remove the oils as well. Tools exposed to the plant, especially its sap, should not be reused or handled without thorough cleansing.

While the hazard of the urushiol makes it difficult to work with this plant, its root systems tends to be shallow and relatively easy to remove. The roots contain the highest urushiol concentrations

When removing from trees, the vine can simply be cut at the base by removing a 1-2" x - section using pruners, lopers or a straight bladed saw (it is difficult to avoid cutting the tree's bark using a curved saw).

When cutting large vines or cutting up trees that are covered in the vine with a chainsaw, always use the top of the cutting blade to throw any sap away from the chainsaw operator.

DisposalEdit

Disposal of poison ivy must always be approached with utmost care, since the plant material, dead or alive always contains urushiol, and can cause the known rash to occur.

It never should be burned, since burning causes the urushiol to vaporize into aerosol, makes it airborne, and can cause severe respiratory problems or even death if inhaled. As it causes your lungs to internally blister next causing you to drown in your own fluids. Vines located on fire wood thoroughly need to be removed prior to burning of wood Poison ivy can be chipped and hot composted, but care should be taken to segregate the chips since they should not be used as uncomposted mulch on pathways.

Illustration
foliage with entire margins
Young foliage with lobed margins
vine on a tree