Because the facility’s focus is on researching and showcasing plants that are hardy in Minnesota’s climate, Arboretum staff decided to use this improvement project to demonstrate how rainwater gardens can be an aesthetic, natural means to deal with stormwater. Bonestroo designed gardens that provide a scenic walk in from the parking lots while improving water quality.

Beneath the plants, two feet of sandy soil filters stormwater, removing sediments and pollutants while helping to replenish groundwater and prevent erosion. Trees and shrubs along the edges help distribute and slow the flow. Even in their inaugural season, the rainwater gardens successfully handled up to three inches of rain in a few hours—beautifully.