First report of Koenigia divaricata in Poland
Koenigia divaricata (Polygonaceae) is a perennial herb native to East Asia (Russia Far East, Eastern Siberia, Mongolia, the Korean Peninsula, Northern China, and Japan). In the EPPO region, it is occasionally utilised as an ornamental species and it has been used as a fodder plant. It is reported as naturalised in Denmark, Finland, Norway, the European part of Russia and Sweden. In Norway and Russia it is considered as an invasive alien plant. K. divaricata was found in September 2021 in Stare Opole near Siedlce, Eastern Poland. It persisted in 2022, surviving the winter and plants developed fruit. Here it was recorded in a grassland site adjacent to the railway line (approximately 30 m from the railway track). There were also other plant species typical of ruderal habitats present(e.g., Saponaria officinalis and Solidago gigantea). Potentially, the occurrence of K. divaricata in Poland is a result of escape from cultivation, or it may have come from Belarus via the railway connection. In Norway, K. divaricata invades constructed sites (e.g., housing areas, industrial sites and roads) suggesting that the seeds or vegetative parts of the plant can be dispersed with soil or on construction machinery. K. divaricata should currently be treated as a casual alien species in Poland, though there is the potential for establishment due to suitable (temperate) climatic conditions.
Sources
Łazarski G, Pliszko A (2023) First record of Koenigia divaricata (L.) T.M.Schust. & Reveal (Polygonaceae) in Poland. BioInvasions Records 12(4), 909–917.