Identifying and limiting the presence of ragweed

Ragweed is a widespread weed in Québec. It is present from May to October and dies at the first frost in the fall. In mid-July, ragweed begins to bloom and produce pollen. The pollen travels through air in a fine dust and causes allergic reactions in people who are sensitive to it. It affects over a million people in Québec between July and October.

Where ragweed is found

Ragweed mostly grows in poor soil. It is mainly found in the following areas:

  • Along streets and sidewalks
  • On the side of paved roads
  • On vacant lots
  • On lands under construction
  • On industrial lands
  • On lands that serve as snow dumps

Identifying ragweed

The appearance and size of this weed vary according to its stages of growth, but it can reach up to 2 metres in height.

The substance responsible for allergies is pollen, which causes seasonal rhinitis.

Distinguishing ragweed from poison ivy

Ragweed is often confused with poison ivy. The appearance of these two plants is very different and they do not have the same impacts on health. It is important to distinguish both.

Poison ivy can grow up to a meter tall.

Poison ivy leaves have a smooth or slightly jagged edge. They are glossy and their colour varies; wine red in the spring, and dark green in the summer; in the fall, they are multi-coloured.

The plant contains a toxic sap that causes an allergic reaction of the skin.

For more information on the differences between the 2 plants, read “Identifying poison ivy” on the Identifying and getting rid of poison ivy page.

Limiting the presence of ragweed in your surroundings

Pollen from ragweed is the main cause of seasonal rhinitis, which affects 1 in 5 people in Québec. The best way to reduce the impact of ragweed is by eliminating it from your surroundings. To achieve this, you may do the following:

  • Pull or mow the ragweed on your land
  • Prevent ragweed from growing 

Pulling or mowing ragweed

For small land

On small land, such as a residential one, it is best to pull the ragweed as soon as you spot it. You can pull:

  • By hand
  • By uprooting the plant with a garden tool, such as a hoe

For big land

For larger land, you can cut the plant with a lawnmower. For best results, and to reduce the amount of pollen released as much as possible, mow ragweed twice a year, in mid-July and mid-August.

Pulling and mowing are 2 quick and effective ways to get rid of ragweed from your land.

You can throw the pulled or cut plants with the rest of your garbage. It is not recommended to put them in your compost as the ragweed seeds can contaminate it.

Preventing ragweed from growing

Ragweed does not grow easily on healthy and fertile lawns. To limit the presence of ragweed, you can do the following:

  • Use mulch or groundcover in places where there is no lawn
  • Improve soil quality with compost or fertilizer
  • Sow the land, or plant other vegetation

You can consult a specialist at a garden centre to learn which products are best suited to preventing ragweed from growing on your land.

Last update: June 13, 2023


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