Dragana Skočajić, Mihailo Grbić, Marija Nešić, Ivana Bjedov and Dragica Obratov-Petković
University of Belgrade – Faculty of Forestry, Kneza Višeslava 1, 10030 Belgrade, Serbia
A few years ago, the decorative species Leycesteria formosa Wall. appeared in garden centers and nurseries in Serbia. Native to southwestern China and the Himalayas, this deciduous shrub has also naturalized in some European countries. This species shows great adaptability to different site conditions although it prefers rich soils. It is a fast-growing species with a high number of shoots, easily propagated vegetatively by layering and root fragments which increases the possibility of its spread through human activities. In addition, this plant produces a high number of seeds which are dispersed hydrochorously and zoochorously by birds and mammals.
In order to examine the germination potentials, seeds were collected from parent trees in a private yard in Belgrade. A total of 4 × 50 seeds were placed in laboratory conditions (germination thermostat, germination temperature of 21±2oC and 16/8 photoperiod). Real germination and germination intensity were determined after 14 days, and germination energy after 5 days. The results showed a high germination percentage (98%) and germination energy (84%) two days after the beginning of the experiment. This points to the high degree of seed vitality and intensity of germination, which characterizes potential invasive plants.
Leycesteria formosa is listed as one of the 100 most invasive species in Macaronesia, while the EPPO Reporting Service (2014) points to the need for the monitoring of this species in Great Britain, Ireland, France and Azores. However, due to climate change, the conditions prevailing in the area of Belgrade are becoming quite similar to the ones in the areas from which the species is introduced and further increases the chances of this species to adapt to the new environment and increase its invasion risk. Currently, this species is not observed in natural habitats in Serbia, but its expansion can be expected through sales in nurseries and garden centers. In order to prevent the spread of L. formosa to urban and natural habitats, further careful observations are needed.