Invasive species challenge Rovaniemi as false spiraea removal costs rise in Finland

Invasive species, which spread aggressively, pose significant challenges and costs, and the battle against them is unlikely to end. The latest species classified as harmful is the false spiraea, which cannot be sold, bought, or cultivated after August 2025. This fast-growing plant was widely sold in the 1980s and 1990s for home gardens, parks, and streets. According to gardener Kati Kivelä from Viherlandia in Jyväskylä, it was a “dream plant” for public builders, tolerating road salt and growing quickly.

Viherlandia has not sold the false spiraea for a couple of years, with demand dropping before that. As Kivelä diplomatically points out, the plant does not fit contemporary aesthetic standards—“It is bushy, and now people want compact and pretty plants.” Those already planted, such as a long hedge found near the Rovaniemi railway station, are now issues. City gardener Mirja Vääräniemi estimates over 4,600 square meters of false spiraea on city plots must be removed, a task expected to take at least two or three years of intensive work and potentially another ten years for monitoring and cleanup. The estimated cost for this removal is between €10,000 and €20,000.

Invasive species often spread through seeds transported by birds or garden waste. The false spiraea made its way to Finland via nursery sales, often going unnoticed for years. Despite its harmful classification, it can still be sold for one more year to ensure a gradual phase-out for nurseries.

As the climate warms, northern Finland will likely see the arrival of new invasive species, such as sourgrass, which is particularly problematic for farmers due to its aggressive growth. Rovaniemi is currently addressing another invasive problem: the commonly planted Japanese knotweed, which binds soil but prevents other plants from flourishing. Its status may soon change to harmful, spurred on by pressure for environmental restoration, especially along riverbanks.