The arrival order of species, also known as priority effects, can have big impacts on the future plant community assembly and diversity. Knowledge about priority effects can be of importance in grassland restoration and to counteract invasive species invasion. The aim of this study was to evaluate if and how much plant traits change with arrival order. Here, 15 grassland species, divided into functional groups (forbs, grasses, and legumes) were sown in a greenhouse. The plants were subject to one of three treatments: ‘Control Alone’ (CA), where each plant was grown alone, ‘Control Together’ (CT), where two plants arrived at the same time and ‘Priority effect’ where the first plant (PE.1) arrived three weeks before the second plant (PE.2). For plants grown alone, there was significant differences between the functional groups for the traits mass relative growth rate, height relative growth rate, plant height, plant width and width of stolons. Forbs had significantly largest relative growth rate (RGR), smallest height after three and six weeks of growth as well as largest stolons at both times. Grasses showed significant largest width at three weeks of growth and legumes reached about the same width as grasses after six weeks of growth. The plants that arrived second showed significantly less growth compared to the other treatments which imply that priority effects occurred. The growth strategy for forbs was fast RGR and production of stolons, for grasses it was primarily an increased width and for legumes it was a combination of reaching large height and width.