You can report observations of invasive species on the website of the Finnish Museum of Natural History http://www.vieraslajit.fi (in Finnish)
Some invasive species are deemed so detrimental that immediate effective measures must be taken. The most harmful are hogweeds (Heracleum persicum) and rugosa rose (Rosa rugosa). If you notice these species along highways, you can report it to the Road User Line at 0200 2100 (24 hours a day). They will forward your message to the contractor, who will take control measures according to the contract programme.
People also report cow parsnip (Heracleum sphondylium), garden angelica (Angelica archangelica) and wild angelica (Angelica sylvestris) as hogweeds. These domestic species should not be confused with hogweeds and there is no reason to eradicate them. Garden angelica is protected south of Oulu province. Unless you are sure you can tell the species apart, request for help with the identification.