Invasive plants can have significant ecological effects. Cheatgrass (Bromus tectorum) is of particular concern in North America, where its competitive nature can seriously degrade natural grasslands. This study, conducted in the White Lake Basin region of British Columbia, investigated the impact of cheatgrass on native plant diversity and the relationship between diffuse knapweed (Centaurea diffusa) and introduced grass cover. The study also analysed the association of cheatgrass with other grass species to provide insight in selecting grass seed composition for seeding after habitat disturbance. Results indicated higher native grass diversity in plots without cheatgrass and in plots containing bluebunch wheatgrass (Pseudoregneria spicata). While diffuse knapweed decreased during the study period, due to biological control, invasive grasses increased. Native grass species positively associated with cheatgrass include needle and thread grass (Hesperostipa comata), Sandberg bluegrass (Poa secunda), and sixweeks fescue (Vulpia octoflora), indicating potential for seeding in disturbed areas prone to cheatgrass.