Ragweed (also known as ragweed, ragweed or wild hemp) originates from the north-eastern United States and is increasingly spreading in Europe.

The plant has now also been discovered in some areas of Germany. The inconspicuous plant can trigger severe hay fever and in some cases asthma through inhalation of the pollen or skin contact.

The annual plant is a late bloomer and can flower from July to October. It develops mainly in open areas in fields, on roadsides and in gardens, especially at bird feeding sites from the previous winter due to contaminated bird food, but also in rubble pits and on building sites.

The bunchgrass grows to a height of 30 - 150 cm, has a taproot and green, strongly incised leaves on both sides. The leaves are hairy with whitish veins and are triangular to oval in shape. There is no odor when the leaves are rubbed. The stem is white - reddish, hairy and very branched. The plant bears both male and female flowers, the males forming a spike-like raceme at the end of the branches, each with 5 - 20 tubular yellow-green flowers in a hemispherical sheath. The female flowers are greenish and sit below the male flowers, with an inverted conical involucre. It is often confused with common mugwort, Verlot's mugwort, wormwood, amaranth, goosefoot and common chamomile.