The key is catching the plant when the leaves are new and shiny.
Note: Buy a liquid soap and not a detergent. Health food stores have liquid soaps, such as Dr. Bronner's Pure-Castile Soaps.
4 tablespoons liquid soap
1 quart water
Here is the homemade poison ivy vegetation killer spray that I've found is safe and effective if you are reading this when the leaves are no longer shiny:
Poison Ivy Vegetation Killer
1 cup salt
8 drops liquid detergent
1 gallon vinegar
Combine the salt and vinegar in a pan and heat to dissolve the salt. Cool the vinegar, add the detergent, and pour some of the liquid into a large spray bottle. Spray the vegetation. (You can also just pour the mixture onto the weeds.) Refill the spray bottle as necessary. Note that this formula will kill all the vegetation, so make sure that you are only spraying the plants you want to kill. If you need to use a lot of this spray, avoid spraying it near wells, as the salt can leach into your water supply
What does the poison ivy plant look like?
Poison ivy is the most common and widespread plant of the three. It is characterized by its leaves, which have three or five serrated-edge, pointed leaflets. Its leaves assume bright colors in the fall, turning yellow and then red. Poison ivy grows as a vine or free-standing plant in the East, Midwest, and South and as a shrub in the far northern and western United States, including the Great Lakes and Canada.
What does the poison oak plant look like?
Poison Oak has three oak-like leaves and grows as a low shrub in the East and as both low and high shrubs in the West, where it is most prevalent. Poison oak produces whitish flowers from August to November that dry and can remain for many months. In the fall, the leaves assume bright colors, turning yellow and then red.
Poison sumac has seven to 13 staggered leaflets with one on the tip of the plant and grows as a shrub or small tree. It is found mainly in the eastern United States, growing in peat bogs and swamps. Poison sumac is distinguished from nonpoisonous sumac by the location of its fruit, which grows between the leaf and the branch as opposed to the ends of the branches.
Myths versus Facts
Myth: Scratching poison ivy blisters will spread the rash.
Fact: The fluid in the blisters willl not spread the rash. Before blisters form, the rash can only be spread by unbound urushiol. Avoid scratching of blisters. Fingernails may carry bacteria that could cause an infection.
Myth: Poison ivy rash is "contagious."
Fact: The rash is a reaction to urushiol. The rash cannot pass from person to person after the urushiol binds.
Myth: After the first time, I can't get poison ivy again.
Fact: Although not everyone reacts to poison ivy upon first or subsequent exposures, people generally become more sensitized with each contact and may react more severely to subsequent exposures. In addition, the reaction may last longer.
Myth: Once allergic, always allergic to poison ivy.
Fact: A person's sensitivity changes over time, even from season to season. People who were sensitive to poison ivy as children may not be allergic as adults.