A preliminary field trial to compare control techniques for invasive Berberis aquifolium in Belgian coastal dunes

Non-native Berberis aquifolium is notoriously invasive in Belgian coastal
dunes. With its strong clonal growth through suckers, this evergreen shrub
outcompetes native species and affects dune succession. To prevent further
secondary spread and mitigate its impact, there was an urgent need for
knowledge on the effectiveness of control measures, both at the plant and
habitat level. Here, we report on a first control experiment. Individual
B. aquifolium clones were subjected to one of four treatments (manual
uprooting, foliar herbicide application, stem cutting followed by
herbicide or salt application), with regrowth being measured up to one
year after treatment. Plants proved most susceptible to foliar herbicide
application (5% glyphosate solution), resulting in 77% of the clones
apparently killed. We discuss the limitations of our experiment and the
potential for actual field application of the different treatments. We
present some guidelines for future control that may become further refined
as experience builds up.