Spread potential of Phytolacca americana in Poland
Phytolacca americana (Phytolaccaceae) is native to North America and has become widespread in the EPPO region. It is used as a medicinal plant and can be eaten after it is cooked. Within the EPPO region, the species occurs in clear-cut areas, along hedgerows and wasteland (e.g. in Switzerland), along field margins, canals and coastal areas. The plant is spread mainly by natural means, including by birds feeding and spreading the seeds or by rhizome movement as a result of habitat disturbance.
The spread of P. americana was estimated in the Niemodlin Forest in south-western Poland in 2023 and 2024, using field-collected data and modelling. Surveys were conducted to estimate the extent of the invasion, and other factors (such as plant community structure and soil conditions) were estimated or classified based on current databases. Using data from a wider area, the most important variables for the potential distribution of P. americana are: (1) dominant tree species in the area; (2) extent of environmental degradation; (3) soil type; (4) land use; (5) forest type; (6) soil moisture level; and (7) age of dominant tree species. All of these variables were included in the model along with climatic data. The results showed that 105 square kilometres of the analysed area is suitable for P. americana. To prevent further spread, the following four actions should be taken: (1) eradication of populations in known locations; (2) monitoring spread and rapid eradication of new populations; (3) awareness raising with key stakeholders; and (4) prohibiting the sale of the species for ornamental purposes.
Sources
Tokarska-Guzik B, Dajdok Z, Stefaniak J (2025) The spread of Phytolacca americana (Phytolaccaceae) in the Niemodlin Forest as an example of invasive potential in southern Poland. BioInvasions Records 14(4), 769–788, https://doi.org/10.3391/bir.2025.14.4.03