Heracleum spp.

(giant hogweed) is an alien weed introduced from Western Greater Caucasus in temperate Europe. It impacts on ecosystems because it forms dense stands thus reducing biodiversity. In addition it produces phytotoxic sap, that can cause skin burnings. IPM methods based on mechanical removal, and non-persistent broad spectrum chemicals have been developed in WP3 and validated within WP4 in forestry, river sides, road sides and non-agricultural areas on properties of land owners and municipalities.

Species Description

Hogweeds are from the family Apiaceae or Umbelliferae - aromatic flowering plants and commonly known as the celery, carrot or parsley family. It also includes such well-known and economically important plants such as anise, caraway, carrot, celery, chervil, coriander, cumin, dill, fennel, hemlock, cow parsley, parsley, parsnip and many others. Hogweeds grow up to 2-5 m tall. Stems at the base are usually 5-10 cm Ø. Leaves of mature plants are divided to a varying extent either into three. White or rarely pinkish flowers are clustered in an umbrella-shaped head (umbel) that can be up to 80 cm across. Flowering typically lasts from June to August. Depending on the species, environmental factors, hogweed can flower from the 2nd-3rd year. One hogweed on average forms around 3 – 20 thousand seeds. The life cycle ends with ripening of seeds and finally the plant dies – its mission is over. Distribution of hogweed is only by seeds. Mowing of hogweed prolongs the life cycle and flowering occurs later in the season or in the next year, it can be even delayed up to 10 years or more from germination until flowering. The green oval (elliptic) fruits form by July then turn dry and brown with swollen brown oil canals.


Toxicity and economic significance. Hogweed troubles the use of infested areas, because hogweed sap in contact with skin in presence of ultraviolet rays, results with serious burns of skin. Each year there are new cases of people in EU with serious burns. Photodynamic active substances - furanocoumarins are getting activated, which breaks the DNA protein and kills the skin cells.

Hogweed takes over the entire territory, becoming the monoculture of the site. Hogweed displaces not only the plant biodiversity, but also animals, humans and creates damage to the infrastructure. In the last decades EU countries have spent millions of euros to control hogweed1. Losses are not only economical, but also related with human health, nature biodiversity, road and railway management, municipal management etc.

Management approach

For Optimized chemical control: Herbicides, biological and mechanical control

Solution proposed by EMPHASIS

For Optimized chemical control: Guidelines for sustainable IPM control of weeds in agricultural and non-agricultural areas (PU)

Contact person/organisation

Inga Gaile (IAS)