Perennial ragweed

Short Description

Perennial ragweed can grow to up to 2 metres in height.

The leaves grow oppositely on the stem. They vary widely in appearance and can be entire to divided (pinnate). The underside of the leaves is covered in dense woolly hairs.

The stem is upright with dense white hairs.

The flowers are very inconspicuous and clustered in numerous flower heads. The numerous pendulous flower heads are distributed along the stem.

The seeds are small nut fruits with five to seven blunt protrusions.

In the city

Perennial ragweed is mainly found in road verges, fallow land, gardens, parks and particularly along railway tracks. It prefers sunny, warm sites with nutrient-rich, slightly acidic soil. It also grows in other sites, but not particularly high.

It is generally spread to different sites through transports of contaminated soil as part of building and construction work. Perennial ragweed can trigger strong allergic reactions. For that reason, ragwort is generally removed. Care should be taken to remove as many parts of the root system as possible.