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Rangeland weeds are costly pests, reducing forage, adversely affecting livestock, or increasing producers' expenses. Some, like the invasive Dalmatian toadflax (Linaria dalmatica [L.] Mill.), are considered noxious throughout the west. In contrast, the native Geyer larkspur (Delphinium geyeri Greene) is limited in distribution but associated with high spring cattle mortality. Research that evaluates grazing as a management tool for these two species is limited and sometimes conflicting. Our objectives were 1) to determine effects of sheep grazing on Dalmatian toadflax, Geyer larkspur, and associated vegetation, and 2) to compare grazing to herbicide treatments. We allowed ewes to graze experimental units at a constant stocking rate, but varied grazing timing and frequency. We also applied two herbicide treatments (metsulfuron and chlorsulfuron+aminocyclopyrachlor) in spring 2014. We measured cover, biomass, and weed density. All grazing treatments initially reduced larkspur density and limited its regrowth in the two months following grazing (P<0.0015). However, only herbicide had residual effects on larkspur density in 2015 (P=0.0001). More than 80% of toadflax stems were impacted in all 2014 grazing treatments and events, and 45-70% of stems in 2015 treatments (P<0.0001). In midsummer 2015, chlorsulfuron+aminocyclopyrachlor provided the best toadflax control, and the treatment grazed twice annually appeared to limit toadflax spread better than other grazing treatments (P<0.065). Although perennial grasses were visually impacted by all grazing treatments, we observed biomass production similar to the check in all but one treatment in midsummer 2015 (P=0.0476). Two years may be insufficient time to see impacts of repeated heavy grazing in this study system.