Last year giant hogweed was reported at 486 spots along Flemish roads. The figure is up from 339 the previous year.
Giant hogweed arrived here from the Caucasus in the 19th century. The plant's watery sap contains chemical substances that are activated under sunlight. Contact with the skin can lead to serious burns. The Roads Agency takes note of all sightings. The rise in the number of sightings is being linked to the extra attention this plant is getting. In East Flanders sightings rose from 9 to 37 in only one year.
If the plant has not gained a major foothold it is simply pulled out. Larger cultivations are mowed three times a year for seven years.