Cut plants of Impatiens glandulifera can produce viable seeds
Impatiens glandulifera (Balsaminaceae, EPPO List of Invasive Alien Plants) is native to the foothills of the Himalayas (India and Pakistan) and is recorded as an invasive alien plant in the EPPO region where it is widespread. Typically, I. glandulifera invades wet grasslands and riparian habitats where it can have a negative impact on native biodiversity and ecosystem services. Methods for the control of I. glandulifera include mowing and hand-pulling which can be effective due to its weak root system. Hand-pulled plants and those which have been cut by mowing can be left on the ground. An experiment was conducted near Kraków (Poland) to assess if cut plants at the flowering stage can survive long enough to develop viable seed. In May seedlings collected from several sites were planted in an experimental plot. At the end of August, 20 flowering individuals were cut and left on site, and 20 were left intact. Seed was collected from all plants during September and tested for viability. Plant that were cut survived for about three weeks and developed flowers and produced viable seeds. Plants left intact developed more flowers though they did not develop significantly more viable seeds than the cut ones. The study shows that when cut, I. glandulifera can still develop viable seed. Therefore, to be effective, manual control methods should be conducted earlier in the season before the population is flowering or cut plant material should be collected and disposed of appropriately.
Sources
Najberek K, Myśliwy M, Rewicz A, Solarz W (2026) Plant cuttings of invasive alien Impatiens glandulifera Royle develop flowers and produce viable seeds. Scientific Reports 16, 9371, https://doi.org/10.1038/s41598-025-33573-8