mantegazzianum

Heracleum mantegazzianum, commonly known as giant hogweed, is a flowering plant in the Apiaceae family. Native to the Caucasus region, it was introduced to Europe and North America as an ornamental species in the 19th century and has since become invasive in many areas. It spreads primarily by seed and favours disturbed, fertile habitats.

Giant hogweed is a tall perennial or biennial plant that can reach heights of 2 to 5 meters, with thick, hollow stems that bear purple blotches and coarse white hairs. The leaves are highly divided and can measure up to about 1.5 meters across. In mid to late summer it produces large white flower umbels, sometimes up to 80 centimeters in diameter.

The species inhabits damp, fertile soils along rivers, roadsides, and other disturbed sites. It can displace native vegetation and contribute to soil erosion on riverbanks. A major health concern is its sap, which contains phototoxic furanocoumarins. If the sap contacts skin and is exposed to sunlight, it can cause severe blistering and scarring; eye contact can cause serious injury. Handling plants requires protective clothing and careful disposal to avoid exposure and seed spread.

Management typically emphasizes prevention and rapid containment. Mechanical removal is used for small plants or before flowering, with thorough cleaning of equipment and clothing. Chemical control with herbicides such as glyphosate or imazapyr may be employed by trained personnel, following local regulations. Public reporting and education are important to reduce risks and spread.