First visible results of the eradication campaign against Heracleum mantegazzianum in Slovenia
In Slovenia, Heracleum mantegazzianum (Apiaceae, EPPO List of Invasive Alien Plants) is seldom used as an ornamental plant and is so far only recorded in a few localities. It is considered that this plant escaped from the Ljubljana Botanical Garden in the 1980s to the centre of Ljubljana and spread along railways. By 2011, the H. mantegazzianum population had already spread over 3 ha, but most plants were only confined to a stretch of 0.8 ha along railways.
Eradication started in 2011 in the framework of an awareness raising project named ‘Thuja 2’ lead by a consortium of NGOs. Plants were dug out in June each year and any regrowth was cut later in the season.
After three years during which H. mantegazzianum was removed from the core zone of distribution and three marginal stands, the number of plants with the potential to flower was reduced significantly. However, at least another seven years are considered to be necessary for the complete eradication of H. mantegazzianum in the locality concerned in Ljubljana. In addition, following an active campaign to raise public awareness, H. mantegazzianum has been removed from private gardens in three other towns, to prevent any further escape of the plant into the environment.
Sources
Novak Š, Kus Veenvliet J (2013) [Giant Hogweed (Heracleum mantegazzianum) in Slovenia]. In: Kus Veenvliet J (ed.) Book of Abstracts of the Symposium on Alien species – status, impacts and responses (2013-09-13, Ljubljana) (in press).