Over the course of several years of monitoring new plantings on landowner properties throughout the state, reforestation staff encountered a wide range of herbicide prescriptions, with varying results. Often, staff encountered trees showing a high degree of stress, or even mortality, which appeared to be linked to the herbicide application. The decision was made to test some herbicide treatments in our nursery to see how stock reacted to the chemical at various rates and application timings, under more controlled conditions than what is typically found on outplanted stock. We selected Dupont Oust XP (Sulfometuron Methyl) as our test chemical, since it is the most widely used pre-emergent herbicide currently in use in Wisconsin.