The Chicago Botanic Garden holds the Plant Collections Network, Nationally Accredited collection of Spiraea. Spiraea japonica is a widely used landscape shrub that has recently been showing up on invasive plant watch lists around the country. Our collection of Spiraea japonica contains over 60 cultivars. Fecundity is the ability of an organism to produce offspring. By conducting controlled pollination of our Spiraea japonica collection, we hope to analyze the ability of individual cultivars to produce fertile seeds. Working closely with both plant scientists and Garden curators, participants in this project will conduct controlled pollination of Spiraea japonica, and then collect and count seed from individual plants. Seed will then be scrutinized under x-ray analysis to determine viability. The results of this project could have significant impact on future breeding and development of this important landscape shrub.