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Poison ivy - up close and personal

Leaflets of three, let them be!
Leaflets of three, let them be!

Jill Colton, staff writer

August 29, 2010 — Heat and humidity are the perfect ingredients to cook up a boatload of Poison ivy. However, before you become an itchy victim and need to visit your doctor, read on about what you need to watch out for when it comes to this pesky plant.

Poison ivy (Rhus toxicodendron L.) is a native shrub or vine found throughout southern Canada. According to the Government of Ontario website, Poison ivy is sometimes mistakenly called Poison-oak because some plants have very coarse, ribbed leaflets. Real Poison-oak grows in the southern United States, not in Canada. “Poison ivy is a native species to Canada, it was here prior to the Europeans arriving,” explains gardening expert Mark Cullen.

It's an extremely diverse plant as it grows in all kinds of habitat from deep woods to swamps and roadsides. Cullen says that, “It thrives in the margins of shady areas..where it can get some sun, but not total sun.”

Poison ivy, is a woody perennial and may grow as dwarf, shrubby plants only a few centimetres high that carpet the ground. Although not a true ivy, it will often crawl around the ground in vine-like form and twist around trees and shrubs.

What it Looks Like

Remember the helpful rhyme, “Leaflets of three - let it be!” to help detect poison ivy. The stalk of the middle leaflet is longer than the stalks of the two side leaflets. All three leaflet stalks are joined together at the tip of one much longer stalk which is called the petiole. The leaf colour is bright green and the upper surface is smooth and sometimes has a glossy appearance because of the poisonous oil. However, sometimes as it matures, it can grow more than three leaves, Cullen says. In the sun, the leaves can appear a vivid orange-red colour, but in the shade can appear dull. “In the fall, some of the leaves sometimes turn a muddled yellow.”

Weather Conditions

Poison ivy growth really occurs in the heat of summer, so when there's a proliferation of heat, you can expect to find more patches of this pesky plant. “It's pretty tolerant of drought conditions and cold. It's hearty to zone 3 (Edmonton) it's a real survivor.” Poison ivy spreads by seed, but has an extensive undergrowth. It's a difficult plant to get rid of because killing the aboveground portion does not destroy the entire plant. New shoots may sprout from underground stems at any time.

Controlling Poison Ivy

Getting rid of poison ivy is a real concern. “There are, of course, no chemicals available to the average Canadian to kill it effectively, so the solution is to cut it out or get in there early in the season and pull it out,” suggests Cullen. As Poison ivy is a perennial (the root lives from year to year) Cullen says you can try and starve the root by cutting the top portion of the plant out with a gardening ho, which might be the safest thing to do. “Yank it out at the root as much as you can. When the Poison ivy is young you can actually do this and bring it under control.”

Clothing is also very important. You should always wear gloves and a rain suit while cutting or grubbing and be careful about tool contamination. Mark also suggests cordoning off the infested area with a fence if you have youngsters or pets around.

According to the Government of Ontario website, the herbicide Roundup can be purchased to help deal with the weed. “In a ready-to- use-form, this product can also be used to bring Poison ivy under control earlier in the season. The best time to spray is in early spring when it's emerging out of the ground.”

Harmful Effects

People are poisoned by the plant oil which is found throughout the entire plant. The oil can stick to clothing and be easily transferred to the hands or face by touching or rubbing. Pets can also become contaminated by running through dense patches of the plant. Animals don't react to the poison, but if you touch your pet afterwards, you can easily become poisoned. Individuals vary greatly in susceptibility to poison ivy and some may have never suffered any ill effects. “It's similar to getting a burn on your skin, it's extremley irritating and itchy. The worst thing you can do is to scratch your skin because that makes the irritation worse.”

Coming into Contact

If you come into contact with poison ivy or if an article of clothing is contaminated with oil, you should immediately wash the area with soap and water. Keep lathering the area and rinse thoroughly. To avoid developing a reaction, be sure to wash off the oily material as soon as possible. Consult your physician immediately if a rash develops.

Additional Facts

  • A rash can either appear immediately, or within a couple of days.
  • The reaction can take as long as four weeks to clear.
  • Calamine lotion and oatmeal baths can sooth the itching.
  • There are landscaping services that will remove poison ivy for you.

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