The Common Ragweed is a tall, branched annual weed. It grows in dry fields and pastures at roadsides and uncultivated areas. In South Africa it is fairly localized in urban areas.

Common ragweed is problematic to allergy sufferers. Its pollen season is very long – from October to April, which makes it seven months of the year.

In certain parts of the world up to 1000 pollen grains per cubic metre have been measured.