Bio-retention facilities are becoming an important component of stormwater best management practices. Vegetative health directly affects bio-retention facility success. Bio-retention facilities have characteristically harsh moisture conditions. Credit Valley Conservation is developing bio-retention construction guidelines. Identifying suitable plant species for bio-retention conditions is imperative in doing so. This study aims to use the Happy Plant Model (HPM), an Excel-based model that predicts moisture conditions in bio-retention facilities based on construction design, to predict preferred plant species pre-construction. Through a focused literature review, drought and saturation tolerances were found or estimated. Outputs from the HPM influence the plant species list that is generated. Results show that a preferred plant list can be produced for various moisture conditions based on facility design. With the HPM and Interactive Plant List Model, bio-retention facility designers can predict preferred plant species for pre-construction bio-retention facilities. This study provides a step towards effective bio-retention planting.