An investigation of the invasive shrub European Buckthorn, Rhamnus cathartica L., near Saskatoon, Saskatchewan.
Introduced to Saskatchewan, Canada, in the 1930s as a potential shelterbelt species, European buckthorn (Rhamnus cathartica) is now a predominant understorey shrub in riparian woodlands, aspen (Populus tremuloides) groves and prairie shrub communities around Saskatoon. The oldest shrub found was 56 years. Approximately 90% of fruits and seeds collected in seed traps during 1995-96 were dispersed directly beneath the canopy of mature shrubs. The mean germination rate was 85%, with a mean emergence time of 42 days. The seed bank beneath mature shrubs averaged 620 seed/m2 and was composed entirely of European buckthorn seeds. However, little evidence was found of allelopathic properties. Cutting, and the application of Round-up [glyphosate] to stems and Garlon 4 [triclopyr] to basal bark were the most effective methods of controlling European buckthorn.