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Brush control is often necessary to reduce overabundant shrub species and enhance herbaceous understory conditions. However, simply removing shrubs rarely leads to long-term benefits, especially when understory conditions express low resilience. Results can also vary widely depending on target shrub species and site-specific conditions. To clarify this variability, we established large-scale (200-700 acre) studies and applied herbicide to reduce density of big sagebrush, rubber rabbitbrush, broom snakeweed, and black greasewood at different ecological sites in Utah. In addition, we established replicated small-plot studies to evaluate how various herbicide products impact shrub density and plant establishment of old and new herbaceous species varieties. After five years, sagebrush reduction was much higher (75%) and native herbaceous cover increased to a greater extent on shallow-soil sites compared to deep- soil sites. Over the same timeframe, black greasewood and rubber rabbitbrush rapidly re-sprouted, even though initial mortality was noted after treatment. Heavy livestock grazing greatly weakened understory perennial grasses at rabbitbrush sites, and likely enhanced rapid shrub recovery. In contrast, broom snakeweed was reduced by 25% relative to control areas, and understory vegetation responded through simultaneous reductions in redstem filaree and increases in downy brome relative to control areas. Plant establishment of seeded species did not vary between old and new varieties, but species showed large differences in establishment across sites. Our talk will explore both within-site and among-site variability in vegetation dynamics to reach an understanding of the interactive effects soil pre-treatment conditions, shrub reduction, and herbaceous response.