Killing Invasive Shrubs – Using an Oil-Water Emulsion for Basal Bark Treatments - Julianne Mason, Forest Preserve District of Will County

Basal bark applications of herbicide are an efficient and effective method to kill invasive shrubs.  We put in test plots to evaluate whether lower concentrations of triclopyr herbicide are effective for basal bark applications.  We also tested using the herbicide in an oil-water emulsion for the basal bark treatments, as well as whether 360 degree applications are important.  We found that the oil-water emulsions were just as effective as herbicide in straight bark oil.  We found that many of the treated shrubs took a full year to die, but all of the ones died that had received a proper basal bark treatment of at least 10% triclopyr herbicide.  Most of the invasive shrubs in the test plots were multiflora rose and bush honeysuckles, but the results seem to apply for other species of invasive shrubs.