Invasion of annual brome grass onto rangelands is a major problem in North America and managing and controlling this invasion is a challenge. A new promising option is the herbicide indaziflam which has shown potential for controlling annual grasses within perennial grasslands given its comparatively long residual activity in the soil and minimal injury to perennial species. However, prior field studies have been concentrated in the western United States as annual brome invasion has been especially widespread in this area. The objective of this study was to determine whether indaziflam effectively controls annual bromegrass in Alberta, and what the best rate and timing of application would be. We also wanted to identify non-target effects to native plant species. Field experiments that compared rate and timing of indaziflam were set up in the dry mixedgrass prairie in Alberta and species cover was measured. Two years after treatment, spraying in the fall provided greater control of brome than spraying in the spring. We could achieve at least 70.2% brome control with 95% certainty two years after treatment when spraying 2x the recommended rate in the fall, while spraying 1x the recommended rate achieved at least 55.2% control. At the same time, perennial species cover increased and species richness was maintained.