Various fertiliser and trace element products were applied to small plots (10 m2) dominated by Hieracium species (predominantly Hieracium pilosella) in Central Otago. The object of this study was to assess whether any fertiliser product had any "direct control" effect on Hieracium. Originally, 30 treatments were applied to a series of replicated small plots. At the sites studied, the boron compound Fertiliser Borate FB48 was the only treatment to display directly control on Hieracium. Further research has since concentrated on using boron as a control method. Twenty-three sites in total have developed along this theme covering a large range of climate zones (mainly Otago) and soil types, Boron-containing compounds can selectively control Hieracium (especially H. pilosella) without adversely affecting other plant species present. The timing of treatments and evenness of application is critical. New pasture species can be introduced successfully by traditional methods such as direct drilling and oversowing. Keywords: boron, direct control, fertilisers, Hieracium, seasonal variation, selective control