Technical Abstract: Revegetation of drastically disturbed semiarid lands requires rapid stabilization of ecological process and soil resources. Introduced species have been widely adopted because the slow establishment of native species frequently results in poor ecosystem recovery and further degradation. Little research has documented the managerial possibilities and species interactions associated with simultaneously establishing native and introduced grasses on semiarid lands. We conducted a 3-year experiment at Fort Carson in central Colorado to evaluate changes in plant cover after seeding the native perennial grasses western wheatgrass (Pascopyrum smithii), slender wheatgrass (Elyus trachycaulus), thickspike wheatgrass (Elymus lanceolatus), Indian ricegrass (Achnatherum hymenoides), sideoats grama (Bouteloua curtipendula), blue grama (B. gracilis), and sand lovegrass (Eragrostis trichodes) simultaneously in 5 mixes with 2 varieties of Russian wildrye (Psathyrostachys juncea), 2 varieties of crested wheatgrass (Agropyron sp.), or Siberian wheatgrass (A. fragile). The 5 native-introduced grass mixes were compared to a military seed mix. Rapid establishment of the crested and Siberian wheatgrasses treatments maintained significantly lower native grass establishment and weed abundance during the 3-year experiment. In contrast, the Russian wildrye and military treatments had low introduced grass cover and high weed abundance. However, weed cover decreased to less than 5 percent in all treatments during the experiment. Wester, slender, and thickspike wheatgrasses were responsible for over 80 percent of the native species cover in the military and Russian wildrye treatments for all 3 years. We discuss these results and provide insights into managerial considerations for revegetation and weed control.