Poison Ivy


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What is it?

Poison ivy is a straggling or climbing woody vine that's well known for its ability to cause an itchy rash.

Poison ivy can be found in every province except Newfoundland. It grows on sandy, stony, or rocky shores, and sprouts in thickets, in clearings, and along the borders of woods and roadsides. This glossy perennial can spread by seed or by producing shoots from its extensive underground stems.

Should I be concerned?

All parts of the poison ivy plant, including the roots, contain the poisonous resin urushiol. Contact with any broken part of the plant may cause a reaction. Most people develop symptoms 24 to 48 hours after contact. The extent of a reaction depends on the person's sensitivity and the amount of sap in contact with their skin. The inflamed areas often develop blisters, which leads to intense itchiness.

The rash spreads through exposure to the sap, not from the sores themselves. So a person has to actually come into contact with the sap (not necessarily with the plant) before developing an allergic reaction. Contact with a surface that has picked up sap from the plant (like the fur of an animal) can also result in a reaction.

If poison ivy is burned and the smoke is inhaled, the rash will appear on the lining of the lungs, causing extreme pain and possibly fatal breathing problems. If poison ivy is eaten, the digestive tract, airway, kidneys, or other organs can be damaged.

Did you know?

  • Poison ivy belongs to the same plant family as the trees producing the mango and the cashew nut.
  • Urushiol oil is so potent that only one nanogram (billionth of a gram) is needed to cause a rash.
  • No animal can get a rash from poison ivy, but they can get the urushiol oil on their fur.
  • Goats and other grazers eat poison ivy, and birds eat the seeds.

What does poison ivy look like?

The leaves of poison ivy have three pointed leaflets. The middle leaflet has a much longer stalk than the two side ones. The leaflet edges can be smooth or toothed, but are rarely lobed. The leaves vary greatly in size, from 8 to 55 mm in length. They are reddish when they appear in the spring, turn green during the summer, and become various shades of yellow, orange, or red in the fall.

The plant stems are woody and of two kinds. The most common kind grows as a trailing vine, with upright leafy stalks 10 to 80 cm (4 to 31.5 inches) high. The second kind is an aerial vine that may climb from 6 to 10 m (6.5 to 11 yards) high on trees, posts, or rough surfaces.

The plant produces clusters of cream to yellow-green flowers during the months of June and July. The berries that appear by September are clustered, round, waxy, and green to yellow in colour. The size of the berries ranges from 3 to 7 mm (.12 to .28 inches) in diameter, and they often remain on the low, leafless stems of the plant all winter.

Poison ivy is often confused with similar plants like poison oak and poison sumac. Poison oak has the most "oak-looking" leaves of any of the species. It usually has multi-lobed leaves, no aerial roots on the stems, and fuzzy fruits and leaves. Poison oak is not usually found in Canada, except for a western species that grows in southern British Columbia.

Poison sumac, which tends to grow in wet soil conditions, has tiny sweet-smelling flowers in the spring. It is brightly covered with lovely red and yellow leaves in the fall, with 7 to 15 leaflets. Poison sumac never has only three leaflets, and is the only one of the three that has cream-coloured berries.

Poison ivy, poison oak, and poison sumac can all cause skin rashes (dermatitis) from the urushiol in their sap. When in doubt, avoid touching an unknown plant until it has been clearly identified.

What should I do if I get poison ivy on me?

Wash any areas of your skin you think may have come in contact with poison ivy with soap and cold water. Cold water should be used, because hot water tends to open the pores, increasing the chances of the resin being deeply absorbed into your skin. If soap is not available, vinegar (2 tablespoons in 1 cup of water) or alcohol (1/2 cup to 1/2 cup of water) can be used.

These practices may not prevent a reaction, but will likely prevent the infection from spreading. If a reaction does develop, see your doctor for treatment. Skin irritation (itching, red inflammation, blisters and, in severe cases, oozing sores) resulting from exposure to poison ivy normally disappears in 7 to 15 days.

How can I get rid of poison ivy?

Protective clothing

When working in or near poison ivy, always wear gloves and protective clothing to make sure that no area of your skin is exposed to the sap of the plant. Poison ivy sap can stick for long periods to clothing, tools, and the coats of pets and livestock. Under hot, humid conditions, the sap becomes inactive in about a week. Under dry conditions, it can retain its harmful effect for as long as one year or more.

Any clothing worn while working in or near poison ivy should be carefully removed, washed in hot, soapy water, and hung outside to dry for several days. Remember to wear gloves while handling objects that may be contaminated. Do not wash clothing suspected of having sap on it with other laundry, to avoid any further contamination. You may need to repeat washing to get all the sap off.

Cultivation

For effective control of poison ivy, the reproductive ability of the plant can be disrupted by destroying its roots and stems.

  1. Pay close attention when clearing dead vegetation in early spring or late fall. Learn to recognize and carefully handle any poison ivy plant material.
  2. Dig out and hand pick the roots and stems.
  3. Work the soil frequently to reduce the ability of the plant to produce shoots. This will eventually eliminate poison ivy because the plant does not regenerate easily from plant fragments.
  4. Since loose seeds may be hard to detect, remove any dead plant material from the ground, in case some seeds are still attached to the stems.

Products

Important!

If you use a pesticide to control your pest problem, read the label to make sure you are choosing the right product for the right pest. Follow all label directions and warnings carefully. Always look for a Pest Control Products (PCP) number on the label so you know the product has been approved by Health Canada. See Use pesticides safely for more information on using pesticides safely

Did you know?

Some provinces and municipalities have placed more restrictions on the use of certain approved lawn and garden pesticides. Please check with your city, province, or local lawn care centre for more information

Applying herbicides to control poison ivy can be effective. One treatment may be enough, though it is possible for regrowth to happen, particularly where treated plants have been growing for two years or more. You may need to repeat the treatment as often as regrowth appears. Applying herbicides by spot-treatment will help to reduce the chances of the product drifting onto other plants. Herbicide spot treatment is also recommended when poison ivy is a lawn weed.

Pesticides for consumer use can usually be bought through garden centres or hardware stores. Buy only those products whose labels indicate poison ivy control.

Disposal of poison ivy

Important!

Do not burn poison ivy! This may release the poison into the air, in the form of tiny droplets carried by the ash and dust particles in the smoke. A severe reaction may happen if a sensitive person inhales or is exposed to this smoke.

Dead poison ivy plants can still cause rashes and must be handled with care, since the urushiol oil can stay active on any surface for up to 5 years. Dispose of them by placing them in a garbage bag. Make sure that bags containing poison ivy are sealed, well identified, and disposed of with household garbage.

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