Long-term reassessment of floristic diversity in created wetlands is needed to gain an understanding of how wetlands created for mitigation mature floristically. A thorough floristic survey of a 17-year old created wetland in southeastern New Hampshire was conducted to compare current data to a 1992 floristic study of the site. The flora in 2002 included 110 species, whereas the total number of species recorded in 1992 was 101. Not only had diversity increased, but the flora had changed in a 10-year span; the floristic lists of the two years showed 79 shared species. Sørensen's Index of Similarity revealed a floristic similarity of 75%. Carex atherodes, new to the site in 2002, represents a new state record for New Hampshire. As there is a great need for long-term evaluation of mitigation wetlands, these data contribute toward a better understanding of the maturation of created wetlands, and can be used to make more meaningful floristic comparisons with natural wetlands and evaluate the long term success of wetland mitigation projects.