Poison Ivy, Toxicodendron radicans

Poison Ivy — The Plant Nobody Wants

First comes the itching, then a red rash, and then blisters. These symptoms of poison ivy (Toxicodendron radicans) can emerge any time from a few hours to several days after exposure to the plant oil found in the sap of this poisonous plant. The culprit: the Urushiol Oil.

Urushiol Oil. The name urushiol is derived from the Japanese word for lacquer, urushi, and it is a toxin that reacts upon skin contact, creating blistering and rashes. Urushiol is an oil made up of numerous toxic compounds and is contained in the plant’s sap. All parts of a plant with urushiol are poisonous.

Despite its name, poison ivy is not poisonous. It carries an oily sap on its leaves and stems called urushiol, which is irritating to most people’s skin — 85 to 90 percent of people are allergic to poison ivy’s urushiol to some degree, while the rest lack sensitivity to this oil. You can occasionally see the urushiol oil as black spots on poison ivy leaves. Urushiol is what gives poison oak and poison sumac their evil power, too.

Poison Ivy, meanwhile, has become more widespread and toxic in recent years due to higher levels of carbon dioxide. An abundance of Poison Ivy can be detrimental to forests and nature areas, too. As it continues to grow and expand, it could potentially dominate the native vegetation and become a management concern.

Despite being a nuisance to people, poison ivy is an important member of the ecosystem. Its leaves, stems and berries are food for animals, and its vines can be shelter for small animals such as toads and mice, even helping them climb trees.

Here are some tips to avoid it.

Graphic: warning sign for poison ivy

Recognizing Poison Ivy

Found throughout the United States except Alaska, Hawaii, and parts of the West Coast. It can grow as a vine or small shrub trailing along the ground or climbing on low plants, trees and poles. Each leaf has 3 glossy leaflets, with smooth or toothed edges. Leaves are reddish in spring, green in summer, and yellow, orange, or red in fall. May have greenish-white flowers and whitish-yellow berries.

  Leaves of three, leave them be.

Poison Ivy Is Not Contagious

Poison ivy and other poison plant rashes can’t be spread from person to person. But it is possible to pick up the rash from plant oil that may have stuck to clothing, pets, garden tools, and other items that have come in contact with these plants. The plant oil lingers, sometimes for years, on virtually any surface until it’s washed off with water or rubbing alcohol.

The rash will occur only where the plant oil has touched the skin, so a person with poison ivy can’t spread it on the body by scratching. It may seem like the rash is spreading if it appears over time instead of all at once. But this is either because the plant oil is absorbed at different rates on different parts of the body or because of repeated exposure to contaminated objects or plant oil trapped under the fingernails. Even if blisters break, the fluid in the blisters is not plant oil and cannot further spread the rash.

Do NOT Burn Poison Ivy

Burning poison ivy in a brush pile can lead to serious injury. The poisonous oil can become an aerosol that can not only impact bare skin, eyes and mouth, but can cause serious harm to your lungs.

Tips For Prevention

Poison Ivy
Toxicodendron radicans
Plant Type: Deciduous shrub
Height: 1 to 3 feet
Blooms: May - July
Color: Greenish-white
Zone: 4 - 10
Sun: Full sun, part shade

An ounce of prevention is worth more than days of itching!

  Learn what poison ivy looks like so you can avoid it.
  Wash your garden tools and gloves regularly. If you think you may be working around poison ivy, wear long sleeves, long pants tucked into boots, and impermeable gloves.
  Use a poison ivy barrier cream before working in the garden (e.g, X-Ivy)
  Wash your pet if it may have brushed up against poison ivy, oak, or sumac. Use pet shampoo and water while wearing rubber gloves, such as dishwashing gloves. Most pets are not sensitive to poison ivy, but the oil can stick to their fur and cause a reaction in someone who pets them.
  Wash your skin in soap and cool water as soon as possible if you come in contact with a poisonous plant. The sooner you cleanse the skin, the greater the chance that you can remove the plant oil or help prevent further spread.

Tips For Treatment

Poison ivy rash on an arm

Don’t scratch the blisters. Bacteria from under your fingernails can get into them and cause an infection. The rash, blisters, and itch normally disappear in several weeks without any treatment.

You can relieve the itch by:

  Using wet compresses or soaking in cool water.
  Applying over-the-counter (OTC) topical corticosteroid preparations (like Cortizone) or taking prescription oral corticosteroids.
  Applying topical OTC skin protectants, such as zinc acetate, zinc carbonate, zinc oxide, and calamine dry the oozing and weeping of poison ivy, poison oak, and poison sumac. Protectants such as baking soda or colloidal oatmeal relieve minor irritation and itching. Aluminum acetate is an astringent that relieves rash.

See the doctor if:

  You have a temperature over 100 degrees Fahrenheit.
  There is pus, soft yellow scabs, or tenderness on the rash.
  The itching gets worse or keeps you awake at night.
  The rash spreads to your eyes, mouth, genital area, or covers more than ¼ of your skin area.
  The rash is not improving within a few weeks.
  The rash is widespread and severe.
  You have difficulty breathing.

Further Information:

 7 Beneificial Insects
 Climate Change Impacts On Wisconsin
 How Do Earthworms Help Your Garden?
 Soil Biology

Beneficial Species
Fertilize & Mulch
Garden Plans
Garden Pests
Lawn Management
Quick Tips
Soil Management
Specialty Gardens
Bees flying footer graphic