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In the Northern Great Plains, Bromus inermis (smooth brome) and Poa pratensis (Kentucky bluegrass) are substantial threats to remnant prairies by forming monotypic stands that are resistant to restoration while decreasing diversity and altering nutrient cycling. To prevent future spread of these species, we must first understand their invasion process. Invader traits are factors that substantially contribute to invasion potential. The objective of this study was to investigate competition as a trait that may contribute to the invasiveness of B. inermis and P.  pratensis. The study was addressed with a competition experiment in a greenhouse. Each invader was grown alone, with a conspecific neighbor, and a native neighbor (Elymus canadensis). Additionally, three treatments were included to examine differences in phenology between the invaders and the native.  Treatments included planting both species concurrently, planting the invader first (by 21 days), and planting the native first (by 21 days). Final aboveground biomass and a relative interaction index were used as response variables to determine the competitive ability of each species. Both competition (p=<0.001 F=85.361, df=5) and phenology (p=0.001, F=6.859, df=2) treatments were significantly different from each other. Results suggest that B. inermis is a strong competitor that can benefit from early growth, and that P. pratensis is a weaker competitor depending on emergence time. Our results also suggest that native E. canadensis is a strong competitor against these invaders.