Herbicide treatments were applied to Zerene silverspot (Speyeria = Argynnis zerene zerene) post-diapause larvae and early blue violets (Viola adunca), the larval host plant of the Zerene silverspot butterfly, in two greenhouse experiments in 2018-2019. Treatments included distilled water for untreated (U), Agri-Dex (A), Nu Film IR (N), clopyralid (C), clopyralid with Agri-Dex (CA), clopyralid with Nu Film IR (CN), fluazifop-p-butyl (F), fluazifop-p-butyl with Agri-Dex (FA), and fluazifop-p-butyl with Nu Film IR (FN). Zerene silverspot responses measured in the 2018 experiment included larval and pupal survival, sex ratio, larval and pupal development time, pupal and adult mass, adult morphology, female fecundity, and offspring survival and development time. In the 2019 experiment, the recorded response was displayed oviposition behavior of untreated Zerene silverspot females on early blue violets treated with U, CA, and CN. Host plants were also measured for their carbon and nitrogen contents. An additional experiment in 2019 recorded the adult mass of females that were either reared on early blue violets in competition with false dandelions (Hypochaeris radicata) and tall fescues (Festuca arundinacea) or without competition when they were post-diapause larvae.