Plant cover data were collected in experimental plots at two sites, one at Badlands National Park, South Dakota, and one at Scotts Bluff National Monument, Nebraska. At each site, 40 50 x 50 m plots were assigned randomly to one of the following treatments: control (no action), burn-only (prescribed fire in fall 2016), burn+herbicide (prescribed fire followed by imazapic application in fall 2016), and burn+seed (prescribed fire followed by drilling native grass seed in fall 2016). Pre-treatment data were collected in 2015, and post-treatment data were collected in 2017 and 2018. The dataset includes four tables: (1) plant cover and species richness metrics analyzed in the larger work; (2) plant canopy cover data by species; (3) plant species lists for 1 square meter quadrats; and (4) plant species lists for whole plots. The metrics in the first table are calculated from the data in the remaining three tables.