Ragweed

Context

Ragweed (Ambrosia artemisiifolia L.) is a very common weed. The ragweed plant is an annual that grows from May to September and dies at the end of autumn. Although ragweed changes its appearance as the season advances, it retains its jagged leaves, which are similar to the leaves of the carrot plant.

Ragweed can be found in many parts of Québec, where it grows in vacant lots, on the sides of roads and highways, in snow dumps and on residential, commercial and industrial properties.

In people who are allergic to it, ragweed pollen causes hay fever and, sometimes, chronic sinusitis, asthma or conjunctivitis.

Source: Direction de santé publique (DSP) of the Agence de la santé et des services sociaux de Montréal

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Did you know?

Ragweed thrives in soil conditions where other plants have difficulty growing. So it is possible that there are ragweed plants growing on your property or in your environment.
Around mid-July, the male flowers of ragweed, found on spikes at the top of the stem and branches, release pollen into the air. Ragweed pollen is responsible for seasonal allergies that affect one out of every six people in Québec.
On the Island of Montréal, nearly 40,000 children suffer from ragweed-related allergic reactions.
In order to improve the respiratory health of people with allergies, ragweed has to be pulled out, or mowed or cut down before the pollen is released, i.e., in mid-July and in mid-August.

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Are you a health professional?

If you are interested in learning more, read the ragweed page on the Web site of the Director of Public Health for the Montreal (in French only).

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Practical advice

What can you do to protect yourself?

How to recognize ragweed

Read the Ragweed, pull it up! information card.

Do not confuse ragweed and poison ivy. They aren't the same!

If you are allergic

Stay away from places where ragweed is growing.
Keep your doors and windows closed, especially at night, because ragweed releases its pollen early in the morning.
Avoid outdoor activities when the concentration of pollen in the air is high (especially between 7:00 a.m. and 1:00 p.m., when the weather is hot, dry and windy) (check the Pollen Forecast). After a rainfall, pollen grains are precipitated to the ground, thereby reducing allergic reactions.
Avoid mowing your own lawn or raking up leaves yourself.
Avoid drying your clothes outside from mid-July to the end of September.
As needed, use an air conditioning or air filtering system. Keep the filters clean.
Avoid contact with other irritants, such as tobacco smoke, which can aggravate allergy symptoms.
See a doctor if the symptoms persist or worsen or if they make it hard for you to function normally.

To learn more on the subject, visit the ragweed page on the Government of Québec Web site.