Giant hogweed

Heracleum mantegazzianum


The giant hogweed counts among the largest herbs in Europe. The plant can reach a height up to 3 or 4 m. Originally the giant hogweed grows in the Caucasus. It was introduced in Central and Western Europe as ornamental plant and for apiculture.
The hollow stem is light green with reddish spots and white hair. Its diameter can reach 10 cm at the base. The plant has deeply incised, alternate leaves with pointed ends. The leaves that are located at the base usually have a length of 1,5 to 3 m.
The giant hogweed is caracterized by one main florescence in the center surrounded by further flowers. The main flower has a diameter of 20 to 50 cm and is usually located beneath the secondary flowers. Flowers are white.
The biannuel or short-lived perennial plant flowers once between the beginning of June and the end of July. It produces an average of 20.000 seeds and dies afterwards.
The plant can only be confused with the – in every aspect - much smaller common hogweed (or cow parsnip). The common hogweed’s stem is uniformly coloured (green, violet or both) and does not have the reddish spots of its larger cousin.

Did you know?

The giant hogweed is a phototoxic plant. Its sap removes the natural protection of our skin against the sun’s UV-rays. In combination with sunlight, this can cause severe burns, difficult to heal and causing black or purplish scars that can last several years. So please pay attention not to touch the plant without protective clothes and equipment.

Giant hogweed
Foto: M. Pfeiffenschneider