Combating invasive alien species

Invasive species spread rapidly and are a threat to our indigenous plants. They often spread from private gardens and yards and should therefore be removed from your own land, as well as from public green areas.

The most harmful is the poisonous giant hogweed (Heracleum), which must be removed by trained professionals; if you come across any giant hogweed, please notify the Urban Environment Division either online  or by calling Customer Service, tel. (09) 310 22111.

The giant hogweed is an extremely harmful invasive species and should be exterminated only by professionals.

Other invasive species, such as the Himalayan balsam (Impatiens glandulifera ), large-leaved lupine (Lupinus polyphyllus), knotweed (Fallopia) and goldenrod (Solidago), can be uprooted by volunteers. The rugosa rose (Rosa rugosa) is also harmful along shorelines, where it can spread rapidly and take over the entire area.

The Urban Environment Division supports volunteer work by removing all the plants that have been collected. If you would like to gather a team of volunteers to help remove invasive species, notify the volunteer coordinator,, in order to make all the necessary arrangements with the Urban Environment Division.

The Urban Environment Division organises group activities to remove invasive species from May till September. Please check times and dates on the Upcoming Events section.

Similar activities are also organised by the Nature Conservation Society of Helsinki (Helsingin luonnonsuojeluyhdistys).

Guidelines for combating invasive species can be found here: Haitallisten vieraskasvilajien torjuntaohje (in Finnish)

You can also refer to the invasive species online portal: (in Finnish)


Himalayan balsam

Himalayan balsam shoot