Abstract: Successful invasive species can provide insight to factors that are critical in the initial colonization process. The purpose of this study was to explore the demographic and genetic factors contributing to the invasion process using a well studied invasive plant species, Silene latifolia. This European native species was introduced to North America approximately 200 years ago and has since spread across the continent. Effects of genetic diversity were examined by varying the number of source populations (one to three) from each continent planted in a single pot. Potential effects of intraspecific interactions were explored by varying densities (competition) with plants grown singly or with a neighbor (low density) and up to six plants per pot (high density). Seeds were germinated in one gallon pots, which were subsequently placed into an exclosure where they were exposed to ambient conditions. I measured reproductive behavior and phenotypic traits (number of leaves, rosette diameter, and bolt height) at weekly intervals. Density in the founding population (single pot) was strongly associated with the growth and reproductive success of the individual plants. Genetic variation had no significant effect on founding population success. Significant continental effects were detected for growth rates, intraspecific interactions, and reproductive success. These patterns suggest a dominant role of demographic factors in determining founding population success in studying variables such as plant growth and reproductive behavior. Although evidence of the role of genetic diversity on founding population is lacking, further analysis on later life stages may lead to more definite conclusions.