Project overview
Vegetated features, such as bioinfiltration basins, rain gardens, and vegetated swales, are frequently recommended as stormwater management strategies because plants are capable of treating stormwater and reducing runoff volume. Their roots stabilize soil and minimize erosion, reducing sediment loading in downstream waters. Roots also aid infiltration by providing pathways for water to flow into the soil, and they take up water, sending it to the leaves, which transpire the water back into the atmosphere. Grass stems slow surface water flow and filter out debris, and many grasses, sedges, and rushes take up nutrients, preventing them from being transported to receiving waters.
However, vegetated stormwater management projects often fail because designers choose plant species that are not suited for the conditions they encounter at project sites: dry upland prairie plants are installed in clay at the bottom of an infiltration basin, salt-sensitive species are planted next to salt-treated roads, and delicate, short-lived and slow-to-establish perennials are planted where they experience high weed pressure and a little to no maintenance.
Designers need to know which species are adapted to these unique site conditions. To address this need, The Blue Thumb Plant Finder, an online, searchable database of plants for stormwater management, was developed in 2009. However, it was not truly useful for larger scale projects - its plant list was short, it lacked vital information about plants’ traits, and it was not easily searchable.
Research questions
- For this tool to be of use to both the general public and stormwater professionals, which plant species should be included in the dataset?
- What species-level information do stormwater stewards need in order to select species that are adapted to each project site’s unique conditions?
- What is the best way to display, filter, and search this dataset?
Research findings
- For the species selection tool to be useful for stormwater practitioners and the general public, the species included need to be native to the project location’s region, ecologically equipped to survive at the project site, and commercially available.
- In order to plan successful vegetated stormwater management projects that will thrive, stormwater professionals said they need to know about each species’
- native range
- pollinator forage value
- rate of spread
- ability to stabilize soils
- salt tolerance
- flooding tolerance
- herbivore sensitivity
- soil requirements
- The updated tool draws from the authoritative reference book Plants for Stormwater Design: Species Selection for the Upper Midwest by Dan Shaw and Rusty Schmidt, and provides 23 filterable categories that planners can use to “describe” their site and their project goals. The resulting lists will contain species that are likely to thrive at the project site and accomplish the project planner’s goals.
Key innovations/contributions
This project improved the existing Plant Finder tool, producing an online, searchable, native plant species database, designed to help Minnesota stormwater practitioners and residents develop site- and project-specific lists of plant species.
What does this mean for Minnesota?
The improved Plant Finder tool helps designers select native plant species that will thrive in vegetated stormwater management sites and home gardens. When the right plants are selected, projects are much likelier to succeed, making vegetated strategies a more attractive option for municipal planners. This means more runoff is directed to rain gardens and other vegetated stormwater management features instead of to local lakes, rivers, wetlands and streams.
Tools and guidance documents
Reports and Presentations
- Research Brief 2026
- Final Report 2024