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Ragweed and other pollens

The Outaouais region is rich in vegetation, a lot of which can cause allergies. The city of Gatineau, for example, is exposed to a large amount of pollen originating from the Gatineau Park. In Outaouais, it is estimated that one out of every five people suffers from allergies caused by airborne pollen. Even when the allergies are not life-threatening, they still affect quality of life. Certain people have such severe allergies that they have great difficulty carrying out their regular tasks and are housebound during the period in which the pollen is in high concentration in the air.

All plants and trees that cause respiratory allergies are pollinated by wind and not by insects. Plants and trees causing allergies vary, depending on the time of the year:

April to June: birches, poplars and common willows.

May to July: hay (true grasses) that are left to pile up in herring-boat pattern.

August to October: Ragweed and Artemisia (this plant is an allergen like ragweed, but not as strong).

Ragweed: the main culprit

Ragweed is often found where the ground has been freshly disturbed. It grows in places where other plants have difficulty growing. Its presence can affect people up to a kilometer away.

The highest concentrations of ragweed are found in the vicinity of the city of Gatineau and along the Outaouais River.

Characteristics of Ragweed

• Its leaves are dentated in a grayish-green on both sides and resemble carrot leaves;
• The stem has small green or sometimes reddish hairs;
• The male flowers grow in clusters at the tips of the stems and produce pollen allergens;
• The roots are shallow, so they are easy to pull out; and
• They can range in height from 5 to 70 cm and can be up to 1.5 m long.

The ragweed plant is harmless if it comes into contact with the skin. It is not to be confused with poison ivy. To learn the difference between these two types of plants, consult the leaflet: Pdf document. Ouvre une nouvelle fenêtre. L'herbe à poux et l'herbe à la puce…Ce n'est pas pareil… 
PDF File: 3.6 MB | Available in French only

Ragweed can be found in parking lots, municipal parks, recently dug-up vacant lots, gravel roadsides, along train tracks and embankments.

The best way to get rid of ragweed is by eradicating the plants before the pollen spreads, in either May, June or July. Since it is an annual plant, it is unlikely to return the next year after it has been uprooted. Because it needs a lot of light and does not fare well in the face of competition, you can also impede its growth with certain techniques like planting competing vegetation around it. This technique consists of spreading a mixture of plant seedlings that will gradually spread along the ground; they could either be legumes or flowering plants. If the canopy of legumes, for example, has difficulty succeeding following harsh winter conditions, it will be replaced by other plants in the vegetation mixture. The ragweed will gradually lose its place and will be overtaken by the new plants.

How do you protect yourself from allergens?

• Learn how to identify the plants that cause allergies, especially ragweed;
• Pull these plants out of your lawn and from around your property;
• Alert your municipality if you spot ragweed in a vacant lot or on municipal property; and
• Get involved on a citizen action committee to eradicate ragweed from your community.

Do you suffer from seasonal respiratory allergies?

• Try as much as possible to be in air-conditioned spaces;
• Avoid outdoor activities, especially between 7 am and 1 pm, when it can be hot, dry and windy, because that is when the pollen concentration in the air is at its highest;
• Get two types of antihistamines and alternate between them;
• Avoid hanging your laundry outside because pollen can stick to it and be brought inside the house;
• Avoid mowing your lawn yourself; and
• Avoid contact with other irritants like cigarette smoke.

Useful links

Connaître les habitudes de l'herbe à poux

Ministère de la Santé et des Services sociaux - L'herbe à poux Ouvre une nouvelle fenêtre.

Pdf document. Ouvre une nouvelle fenêtre. Notre santé et notre environnement en Outaouais - Les grands responsables des allergies 
PDF File: 88 KB | Available in French only