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Rangeland management is currently challenged by the emergence of novel ecosystems, many of which developed with the invasion of exotic species. Kentucky bluegrass (Poa pratensis) and yellow sweet clover (Melilotus officinalis) are exotic invaders currently degrading native rangelands by altering ecosystem processes and reducing plant diversity. Understanding the mechanisms behind Kentucky bluegrass establishment and its interactions with other species will advance current strategies to control its invasion. Therefore, we determined how increased soil nitrogen from exotic yellow sweet clover impacts both the growth of and competition between native western wheatgrass (Pascopyrum smithii) and invasive Kentucky bluegrass. In a controlled greenhouse environment, we grew�Melilotus�in pots and killed each plant by clipping at the soil surface after eight weeks of growth. We transplanted three different�Poa�and�Pascopyrum�seedling combinations into pots both with and without increased soil nitrogen from�Meliltous�roots. Treatments were replicated four times with ten pots per replication in a randomized block design. Laboratory analyses indicated that�Melilotus�treated soils experienced a 248.35% increase in nitrates and a 348.37% increase in ammonium over control soils. Above-ground biomass production of both�Poa�and�Pascopyrum�grown alone and in competition with one another increased in soils with enhanced nitrogen. However, when grown together in�Melilotus�treated pots,�Poa�biomass increased (520.80%) two-fold over that of�Pascopyrum�(257.05%). Our results indicate that Kentucky bluegrass is able to utilize more increased soil nitrogen than native grasses, such as western wheatgrass,�which evolved under limited, rather than excess soil nitrogen. Additionally, these results suggest that yellow sweet clover may alter the environment in a manner which facilitates the invasion of Kentucky bluegrass. Therefore, control of either yellow sweet clover or Kentucky bluegrass will require management for both exotic invaders.